HTML

1. What is HTML?
      HTML, or HyperText Markup Language, is a Universal language which allows an individual using special code to create web pages to be viewed on the Internet. HTML Code is the code that tells the browser what to do.
2. What is a tag?
      In HTML, a tag tells the browser what to do. When you write an HTML page, you enter tags for many reasons — to change the appearance of text, to show a graphic, or to make a link to another page.      
3. What is the simplest HTML page?
  HTML Code:
<HTML><HEAD><TITLE>This is my page title! </TITLE></HEAD><BODY>This is my message to the world!</BODY></HTML>
Browser Display: This is my message to the world!
4. How do I create frames? What is a frameset?
     Frames allow an author to divide a browser window into multiple (rectangular) regions. Multiple documents can be displayed in a single window, each within its own frame. Graphical browsers allow these frames to be scrolled independently of each other, and links can update the document displayed in one frame without affecting the others.
      You can’t just “add frames” to an existing document. Rather, you must create a frameset document that defines a particular combination of frames, and then display your content documents inside those frames. The frameset document should also include alternative non-framed content in a NOFRAMES element.
      The HTML 4 frames model has significant design flaws that cause usability problems for web users. Frames should be used only with great care.
5. How can I include comments in HTML?
      An HTML comment begins with “<!–“, ends with “–>”, and does not contain “–” or “>” anywhere in the comment.
6. What is a Hypertext link?
      A hypertext link is a special tag that links one page to another page or resource. If you click the link, the browser jumps to the link’s destination.
7. What is a DOCTYPE? Which one do I use?
      According to HTML standards, each HTML document begins with a DOCTYPE declaration that specifies which version of HTML the document uses. Originally, the DOCTYPE declaration was used only by SGML-based tools like HTML validators, which needed to determine which version of HTML a document used (or claimed to use).
8. Can I nest tables within tables?
      Yes, a table can be embedded inside a cell in another table. Here’s a simple example:
    <table><tr><td>this is the first cell of the outer table</td>
               <td>this is the second cell of the outer table, with the inner table embedded in it
                   <table><tr><td>this is the first cell of the inner table</td>
                                 <td>this is the second cell of the inner table</td>
                              </tr>
                       </table>
                   </td>
               </tr>
         </table>
      Older versions of Netscape Navigator have problems with tables that are nested extremely deeply (e.g., tables nested ten deep). To avoid problems, avoid nesting tables more than a few deep. You may be able to use the ROWSPAN and COLSPAN attributes to minimize table nesting.
9. How do I align a table to the right (or left)?
      You can use <TABLE ALIGN=”right”> to float a table to the right. (Use ALIGN=”left” to float it to the left.) Any content that follows the closing </TABLE> tag will flow around the table. Use <BR CLEAR=”right”> or <BR CLEAR=”all”> to mark the end of the text that is to flow around the table
10. How can I use tables to structure forms?
      <FORM ACTION=”[URL]”>
         <TABLE BORDER=”0″>
           <TR>
           <TH>Account:</TH>
              <TD><INPUT TYPE=”text” NAME=”account”></TD>
           </TR>
           <TR>
              <TH>Password:</TH>
           <TD><INPUT TYPE=”password” NAME=”password”></TD>
           </TR>
           <TR>
              <TD> </TD>
              <TD><INPUT TYPE=”submit” NAME=”Log On”></TD>
           </TR>
         </TABLE>
       </FORM>

11. How do I center a table?
      In your HTML, use

    <div class=”center”>
        <table>…</table>
    </div>

    In your CSS, use

    div.center {
        text-align: center;
    }

    div.center table {
        margin-left: auto;
        margin-right: auto;
        text-align: left;
    }
12. How do I use forms?
      The basic syntax for a form is: <FORM ACTION=”[URL]”>…</FORM>
    When the form is submitted, the form data is sent to the URL specified in the ACTION attribute. This URL should refer to a server-side (e.g., CGI) program that will process the form data. The form itself should contain

    * at least one submit button (i.e., an <INPUT TYPE=”submit” …> element),
    * form data elements (e.g., <INPUT>, <TEXTAREA>, and <SELECT>) as needed, and
    * additional markup (e.g., identifying data elements, presenting instructions) as needed.
13. How can I check for errors?
      HTML validators check HTML documents against a formal definition of HTML syntax and then output a list of errors. Validation is important to give the best chance of correctness on unknown browsers (both existing browsers that you haven’t seen and future browsers that haven’t been written yet).
      HTML checkers (linters) are also useful. These programs check documents for specific problems, including some caused by invalid markup and others caused by common browser bugs. Checkers may pass some invalid documents, and they may fail some valid ones.
      All validators are functionally equivalent; while their reporting styles may vary, they will find the same errors given identical input. Different checkers are programmed to look for different problems, so their reports will vary significantly from each other. Also, some programs that are called validators (e.g. the “CSE HTML Validator”) are really linters/checkers. They are still useful, but they should not be confused with real HTML validators.
      When checking a site for errors for the first time, it is often useful to identify common problems that occur repeatedly in your markup. Fix these problems everywhere they occur (with an automated process if possible), and then go back to identify and fix the remaining problems.
      Link checkers follow all the links on a site and report which ones are no longer functioning. CSS checkers report problems with CSS style sheets.
14. How do I make a form so it can be submitted by hitting ENTER?
      The short answer is that the form should just have one <INPUT TYPE=TEXT> and no TEXTAREA, though it can have other form elements like checkboxes and radio buttons.  
15. How do I set the focus to the first form field?
      You cannot do this with HTML. However, you can include a script after the form that sets the focus to the appropriate field, like this:

    <form id=”myform” name=”myform” action=…>
        <input type=”text” id=”myinput” name=”myinput” …>
    </form>

    <script type=”text/javascript”>
        document.myform.myinput.focus();
    </script>

      A similar approach uses <body onload=…> to set the focus, but some browsers seem to process the ONLOAD event before the entire document (i.e., the part with the form) has been loaded.
16. How can I eliminate the extra space after a </form> tag?
      HTML has no mechanism to control this. However, with CSS, you can set the margin-bottom of the form to 0. For example:
      <form style=”margin-bottom:0;” action=…>
      You can also use a CSS style sheet to affect all the forms on a page:
      form { margin-bottom: 0 ; }     
17. Can I have two or more actions in the same form?
      No. A form must have exactly one action. However, the server-side (e.g., CGI) program that processes your form submissions can perform any number of tasks (e.g., updating a database, sending email, logging a transaction) in response to a single form submission.
18. How can I use forms for pull-down navigation menus?
      There is no way to do this in HTML only; something else must process the form. JavaScript processing will work only for readers with JavaScript-enabled browsers. CGI and other server-side processing is reliable for human readers, but search engines have problems following any form-based navigation.
19. Can I use percentage values for <TD WIDTH=…>?
      The HTML 3.2 and HTML 4.0 specifications allow only integer values (representing a number of pixels) for the WIDTH attribute of the TD element. However, the HTML 4.0 DTD allows percentage (and other non-integer) values, so an HTML validator will not complain about <TD WIDTH=”xx%”>.
      It should be noted that Netscape and Microsoft’s browsers interpret percentage values for <TD WIDTH=…> differently. However, their interpretations (and those of other table-aware browsers) happen to match when combined with <TABLE WIDTH=”100%”>. In such situations, percentage values can be used relatively safely, even though they are prohibited by the public specifications.
20. Why doesn’t <TABLE WIDTH=”100%”> use the full browser width?
      Graphical browsers leave a narrow margin between the edge of the display area and the content.
      Also note that Navigator always leaves room for a scrollbar on the right, but draws the scrollbar only when the document is long enough to require scrolling. If the document does not require scrolling, then this leaves a right “margin” that cannot be removed.
21. Why is there extra space before or after my table?
      This is often caused by invalid HTML syntax. Specifically, it is often caused by loose content within the table (i.e., content that is not inside a TD or TH element). There is no standard way to handle loose content within a table. Some browsers display all loose content before or after the table. When the loose content contains only multiple line breaks or empty paragraphs, then these browsers will display all this empty space before or after the table itself.
      The solution is to fix the HTML syntax errors. All content within a table must be within a TD or TH element.
22. How do I create a link that sends me email?
      Use a mailto link, for example
      Send me email at
      <A HREF=”mailto:me@mydomain.com”>me@mydomain.com</A>.
23. How can I have two sets of links with different colors?
      You can suggest this presentation in a style sheet. First, specify colors for normal links, like this:

    a:link {color: blue; background: white}
    a:visited {color: purple; background: white}
    a:active {color: red; background: white}

    Next, identify the links that you want to have different colors. You can use the CLASS attribute in your HTML, like this:

    <a class=”example1″ href=”[URL]”>[link text]</a>
    Then, in your style sheet, use a selector for links with this CLASS attribute, like this:

    a.example1:link {color: yellow; background: black}
    a.example1:visited {color: white; background: black}
    a.example1:active {color: red; background: black}

    Alternatively, you can identify an element that contains the links that you want to have different colors, like this:

    <div class=”example2″>…
    <a href=”[URL]”>[link text]</a>…
    <a href=”[URL]”>[link text]</a>…
    <a href=”[URL]”>[link text]</a>…
    </div>

    Then, in your style sheet, use a selector for links in this containing element, like this:

    .example2 a:link {color: yellow; background: black}
    .example2 a:visited {color: white; background: black}
    .example2 a:active {color: red; background: black}
24. How can I show HTML examples without them being interpreted as part of my document?
      Within the HTML example, first replace the “&” character with “&amp;” everywhere it occurs. Then replace the “&lt;” character with “<” and the “&gt;” character with “>” in the same way.
    Note that it may be appropriate to use the CODE and/or PRE elements when displaying HTML examples.
25. Should I put quotes around attribute values?
      It is never wrong to quote attribute values, and many people recommend quoting all attribute values even when the quotation marks are technically optional. XHTML 1.0 requires all attribute values to be quoted. Like previous HTML specifications, HTML 4 allows attribute values to remain unquoted in many circumstances (e.g., when the value contains only letters and digits).
      Be careful when your attribute value includes double quotes, for instance when you want ALT text like “the “King of Comedy” takes a bow” for an image. Humans can parse that to know where the quoted material ends, but browsers can’t. You have to code the attribute value specially so that the first interior quote doesn’t terminate the value prematurely. There are two main techniques:

    * Escape any quotes inside the value with " so you don’t terminate the value prematurely: ALT=”the "King of Comedy" takes a bow”.
    * Use single quotes to enclose the attribute value: ALT=’the “King of Comedy” takes a bow’.

      Both these methods are correct according to the specification and are supported by current browsers, but both were poorly supported in some earlier browsers. The only truly safe advice is to rewrite the text so that the attribute value need not contain quotes, or to change the interior double quotes to single quotes, like this: ALT=”the ‘King of Comedy’ takes a bow”.
26. HTML for Lists
      1. Bulleted Lists: <ul> begins a bulleted, indented list. Each item in the list is then prefaced with the <li> tag. It is not necessary to insert a break at the end of each line — the <li> tag automatically creates a new line.

    * with <li type=disc>
    * with <li type=square>
    * with <li type=circle>

      2. Numbered Lists: <ol> begins a numbered, indented list. Each item in the list is then prefaced with the <li> tag. You need to close the list with the </ol> tag. Note: You can expand the <ol> to specify the TYPE of numbering:

    <ol> 1 (decimal numbers: 1, 2, 3, 4, 5, …)
    <ol type=”a”> a (lowercase alphabetic: a, b, c, d, e, …)
    <ol type=”A”> A (uppercase alphabetic: A, B, C, D, E, …)
    <ol type=”i”> i (lowercase Roman numerals: i, ii, iii, iv, v, …)
    <ol type=”I”> I (uppercase Roman numerals: I, II, III, IV, V, …)
27. How do I eliminate the blue border around linked images?
      In your HTML, you can specify the BORDER attribute for the image:
      <a href=…><img src=… alt=… border=”0″></a>
      However, note that removing the border that indicates an image is a link makes it harder for users to distinguish quickly and easily which images on a web page are clickable.
28. How do I eliminate the space around/between my images?
      If your images are inside a table, be sure to set the BORDER, CELLSPACING, and CELLPADDING attributes to 0.
      Extra space between images is often created by whitespace around the <IMG> tag in the markup. It is safe to use newlines inside a tag (between attributes), but not between two tags. For example, replace this:

      <td …>
      <img src=… alt=…>
      <img src=… alt=…>
      </td>

      with this:

      <td …><img src=… alt=…><img src=… alt=…></td>

      According to the latest specifications, the two should be equivalent. However, common browsers do not comply with the specifications in this situation.
      Finally, extra space between images can appear in documents that trigger the “standards” rendering mode of Gecko-based browsers like Mozilla and Firefox.
29. How can I specify colors?
      If you want others to view your web page with specific colors, the most appropriate way is to suggest the colors with a style sheet. Cascading Style Sheets use the color and background-color properties to specify text and background colors. To avoid conflicts between the reader’s default colors and those suggested by the author, these two properties should always be used together.
      With HTML, you can suggest colors with the TEXT, LINK, VLINK (visited link), ALINK (active link), and BGCOLOR (background color) attributes of the BODY element.
      Note that these attributes are deprecated by HTML 4. Also, if one of these attributes is used, then all of them should be used to ensure that the reader’s default colors do not interfere with those suggested by the author. Here is an example:
      <body bgcolor=”#ffffff” text=”#000000″ link=”#0000ff” vlink=”#800080″ alink=”#000080″>
      Authors should not rely on the specified colors since browsers allow their users to override document-specified colors.
30. How do I get form data emailed to me?
      The only reliable mechanism for processing form submissions is with a server-side (e.g., CGI) program. To send form data to yourself via email, you should use a server-side program that processes the form submission and sends the data to your email address.
31. Can I prevent a form from being submitted again?
      No. The server-side (e.g., CGI) program that processes the form submission must handle duplicate submissions gracefully.
      You could generate the form with a server-side (e.g., CGI) program that adds a hidden field with a unique session ID. Then the server-side program that processes the form submission can check the session ID against a list of previously used session IDs. If the session ID has already been used, then an appropriate action can be taken (e.g., reject the submission, or update the previously submitted data).
      Ultimately, your server-side program must be smart enough to handle resubmitted data. But you can avoid getting resubmitted data by not expiring the confirmation page from form submissions. Since you want to expire pages quickly when they have transient data, you might want to avoid putting transient data on the confirmation page. You could provide a link to a database query that returns transient data though.
32. How can I allow file uploads to my web site?
      These things are necessary for Web-based uploads:

    * An HTTP server that accepts uploads.
    * Access to the /cgi-bin/ to put the receiving script. Prewritten CGI file-upload scripts are available.
    * A form implemented something like this:

    <form method=”post” enctype=”multipart/form-data” action=”submitAction”>
    File to upload: <input type=file name=upfile><br>
    Notes about the file: <input type=text name=note><br>
    <input type=submit value=Press> to upload the file!
    </form>
33. How can I require that fields be filled in, or filled in correctly?
      Have the server-side (e.g., CGI) program that processes the form submission send an error message if the field is not filled in properly. Ideally, this error message should include a copy of the original form with the original (incomplete or incorrect) data filled in as the default values for the form fields. The Perl CGI.pm module provides helpful mechanisms for returning partially completed forms to the user.
      In addition, you could use JavaScript in the form’s ONSUBMIT attribute to check the form data. If JavaScript support is enabled, then the ONSUBMIT event handler can inform the user of the problem and return false to prevent the form from being submitted.
      Note that the server-side program should not rely upon the checking done by the client-side script.
34. How do I change the title of a framed document?
      The title displayed is the title of the frameset document rather than the titles of any of the pages within frames. To change the title displayed, link to a new frameset document using TARGET=”_top” (replacing the entire frameset).
35. How do I link an image to something?
      Just use the image as the link content, like this:
    <a href=…><img src=… alt=…></a>
36. How do I link to a location in the middle of an HTML document?
      There are different ways to fullfil the above requirement
      a. <h2><a name=”section2″>Section 2: Beyond Introductions</a></h2>
      b.<h2 id=”section2″>Section 2: Beyond Introductions</h2>
      c.<a href=”#section2″>go to Section 2</a>
      d.<a href=”thesis.html#section2″>go to Section 2 of my thesis</a>   
37. How do I create a link?
      <A HREF=”http://www.yoursite.com/faq/html/”>Web Authoring FAQ</A>
38. How do I create a link that opens a new window?
      <a target=”_blank” href=…> opens a new, unnamed window.
      <a target=”example” href=…> opens a new window named “example”, provided that a window or frame by that name does not already exist.
39. How do I let people download a file from my page?
      Once the file is uploaded to the server, you need only use an anchor reference tag to link to it. An example would be:
      <a href=”../files/foo.zip”>Download Foo Now! (100kb ZIP)</a>
40. How do I create a button which acts like a link?
      This is best done with a small form:

    <FORM ACTION=”[URL]” METHOD=GET>
        <INPUT TYPE=submit VALUE=”Text on button”>
    </FORM>
41. How can I make a form with custom buttons?
      Rather than a normal submit button (<input type=”submit” …>), you can use the image input type (<input type=”image” …>). The image input type specifies a graphical submit button that functions like a server-side image map.      
    <input type=”image” name=”Send” alt=”Send” value=”Send” src=”send-button.gif”>      
42. How do I specify page breaks in HTML?
       There is no way in standard HTML to specify where page breaks will occur when printing a page. HTML was designed to be a device-independent structural definition language, and page breaks depend on things like the fonts and paper size that the person viewing the page is using.
43. Which should I use, &entityname; or &#number; ?
      In HTML, characters can be represented in three ways:

    1. a properly coded character, in the encoding specified by the “charset” attribute of the “Content-type:” header;
    2. a character entity (&entityname;), from the appropriate HTML specification (HTML 2.0/3.2, HTML 4, etc.);
    3. a numeric character reference (&#number;) that specifies the Unicode reference of the desired character. We recommend using decimal references; hexadecimal references are less widely supported.

44. How do I remove the border around frames?
      Removing the border around frames involves both not drawing the frame borders and eliminating the space between the frames. The most widely supported way to display borderless frames is <FRAMESET … BORDER=0 FRAMEBORDER=0 FRAMESPACING=0>.
      Note that these attributes are proprietary and not part of the HTML 4.01 specifications. (HTML 4.01 does define the FRAMEBORDER attribute for the FRAME element, but not for the FRAMESET element.) Also, removing the border around a frame makes it difficult to resize it, as this border is also used in most GUIs to change the size of the frame.
45. How can I specify background images?
      With HTML, you can suggest a background image with the BACKGROUND attribute of the BODY element. Here is an example:
      <body background=”imagefile.gif” bgcolor=”#ffffff” text=”#000000″ link=”#0000ff” vlink=”#800080″ alink=”#000080″>
      If you specify a background image, you should also specify text, link, and background colors since the reader’s default colors may not provide adequate contrast against your background image. The background color may be used by those not using your background image. Authors should not rely on the specified background image since browsers allow their users to disable image loading or to override document-specified backgrounds.
46. Is it possible to make the HTML source not viewable?
      In short, there is no real method or script for making standard HTML source code not viewable. You may consider doing any of the below if they are concerned about your source code.

    1. Create the web page in Macromedia Flash or a similar program. The visitor would need to download the Macromedia Flash plug-in and would be unable to view the source code for the flash applet.
    2. There are various scripts that will disable the right click feature, preventing the user from saving images or viewing the source. However, this will not protect the source code of your page. For example, Internet Explorer users may still click “View” and “Source” to view the source code of the page, or a user could disable scripts and images can be saved by simply saving the web page to the hard drive.
    3. There are several programs that will help scramble your code, making it difficult (not impossible) to read. Again, this is not going to prevent someone from viewing your code.
47. How do I make a thumbnail for my image(s)?
      Thumbnails are very useful, but they take a little bit of time to make. All you need is a graphics editing program that has functions to resize an image (sometimes it’s under a function called image attributes). Be advised–when you have made a thumbnail, you will need to save it as something different than the original. Also, you will generally want to link to the larger graphic when you are done.
      <a href=”taco.jpg”><img src=”tacot.jpg” width=100 height=25 border=0 alt=”click for larger taco”></a>
48. What is the difference between the HTML form methods GET and POST?
      The method parameter specifies which method the client is using to send information to the WEB server. The method determines which parameter you will find the CGI request data in:

    * POST – post_args
    * GET – http_search_args
49. How do I put sounds for older versions of Internet Explorer?
      For older versions of Internet Explorer, this technique was used <BG SOUND=”sound.ext”>.
50. How to transferring user to new web page automatically?
      You will need to use the below meta tag.
    <META HTTP-EQUIV=”Refresh” CONTENT=”2″; URL=”http://www.yourname.com”>
        Placing the above tag in your <HEAD></HEAD> will load yousite.com in 2 seconds.
        Changing the 2 value on CONTENT=”2″ to another value will increase or decrease the delay until loading the new page.
51. I’m trying to `include’ a HTML document in another document…Is there a way to do this?
      SGML already provides the standard way to do this, using an entry in the DocType Declaration for a file:

    <!doctype html public “-//IETF//DTD HTML 3.0//EN” [
    <!entity foo system “bar.html”>
    ]>
    …
    and then later when you want to include the file
    …
    &foo;
52. My page looks good on one browser, but not on another.
      There are slight differences between browsers, such as Netscape Navigator and Microsoft Internet Explorer, in areas such as page margins. The only real answer is to use standard HTML tags whenever possible, and view your pages in multiple browsers to see how they look.
53. How do I make sure my framed documents are displayed inside their frameset?
      If the reader’s browser has JavaScript support enabled, the following script will restore the frameset:

    <SCRIPT TYPE=”text/javascript”>
    if (parent.location.href == self.location.href) {
    if (window.location.href.replace)
    window.location.replace(‘frameset.html’);
    else
    // causes problems with back button, but works
    window.location.href = ‘frameset.html’;
    }
    </SCRIPT>
    A more universal approach is a “restore frames” link:

    <A HREF=”frameset.html” TARGET=”_top”>Restore Frames
54. How do I update two frames at once?
      There are two basic techniques for updating multiple frames with a single link: The HTML-based technique links to a new frameset document that specifies the new combination of frames. The JavaScript-based solution uses the onClick attribute of the link to update the additional frame (or frames).

    The HTML-based technique can link to a new frameset document with the TARGET=”_top” attribute (replacing the entire frameset). However, there is an alternative if the frames to be updated are part of a nested frameset. In the initial frameset document, use a secondary frameset document to define the nested frameset. For example:

    <frameset cols=”*,3*”>
    <frame src=”contents.html” name=”Contents”>
    <frame src=”frameset2.html” name=”Display”>
    <noframes>
    <!– Alternative non-framed version –>
    </body></noframes>   
    </frameset>

    A link can now use the TARGET=”Display” attribute to replace simultaneously all the frames defined by the frameset2.html document.
    The JavaScript-based solution uses the onClick attribute of the link to perform the secondary update. For example:
    <a href=”URL1″ target=”Frame1″ onClick=”top.Frame2.location=’URL2′;”>Update frames
    The link will update Frame1 with URL1 normally. If the reader’s browser supports JavaScript (and has it enabled), then Frame2 will also be updated (with URL2).     
55. Can I have two or more Submit buttons in the same form?
      Yes. This is part of HTML 2.0 Forms support (some early browsers did not support it, but browser coverage is now excellent).
    The submit buttons must have a NAME attribute. The optional VALUE attribute can be used to specify different text for the different submit buttons.
    To determine which submit button was used, you need to use different values for the NAME and/or VALUE attributes. Browsers will send to the server the name=value pair of the submit button that was used. Here is an example:

    <input type=”submit” name=”join” value=”I want to join now”>
    <input type=”submit” name=”info” value=”Please send full details”>

56. How do I make a link or form in one frame update another frame?
      in the frameset document (the HTML document containing the <frameset> <frame> tags), make sure to name the individual frames using the NAME attribute. The following example creates a top frame named “navigation” and a bottom frame named “content”:

    <frameset rows=”*,3*”>
        <frame name=”navigation” src=”navigation.html”>
        <frame name=”content” src=”content.html”>
        <noframes><body>
        <!– Alternative non-framed version –>
        </body></noframes>
    </frameset>

    Then, in the document with the link, use the TARGET attribute to specify which frame should be used to display the link. (The value of the TARGET attribute should match the value of the target frame’s NAME attribute.) For example:

    <a target=”content” href=…>
    To target a form submission, use the TARGET attribute of the FORM element, like this:

    <form target=”content” action=…>
    Note that when forms are processed entirely by JavaScript, the target frame must be specified in the JavaScript. The value of the TARGET attribute is irrelevant.
    Normally, the default target frame is the current frame (“_self”). To change the default target for every link/form on the page, use the TARGET attribute of the BASE element, like this: <base target=”content”>
57. When I try to upload my site, all my images are X’s. How do I get them to load correctly?
      They are a few reasons that this could happen. The most common are:

    1. You’re attempting to use a .bmp or .tif or other non-supported file format. You can only use .gif and .jpg on the web. You must convert files that are not .gif or .jpg into a .gif or .jpg with your image/graphics program.
    2. You’ve forgotten to upload the graphic files. Double-Check.
    3. You’ve incorrectly linked to the images. When you are starting out, try just using the file name in the <img> tag. If you have cat.jpg, use
    img src=”cat.jpg”>.
    4. Image file names are case-sensitive. If your file is called CaT.JpG, you cannot type cat.jpg, you must type CaT.JpG exactly in the src.
    5. If all of the above fail, re-upload the image in BINARY mode. You may have accidentally uploaded the image in ASCII mode.     
58. Why does the browser show my plain HTML source?
       If Microsoft Internet Explorer displays your document normally, but other browsers display your plain HTML source, then most likely your web server is sending the document with the MIME type “text/plain”. Your web server needs to be configured to send that filename with the MIME type “text/html”. Often, using the filename extension “.html” or “.htm” is all that is necessary. If you are seeing this behavior while viewing your HTML documents on your local Windows filesystem, then your text editor may have added a “.txt” filename extension automatically. You should rename filename.html.txt to filename.html so that Windows will treat the file as an HTML document.
59. How can I display an image on my page?
      Use an IMG element. The SRC attribute specifies the location of the image. The ALT attribute provides alternate text for those not loading images. For example:

    <img src=”logo.gif” alt=”ACME Products”>
60. Why do my links open new windows rather than update an existing frame?
      If there is no existing frame with the name you used for the TARGET attribute, then a new browser window will be opened, and this window will be assigned the name you used. Furthermore, TARGET=”_blank” will open a new, unnamed browser window.
    In HTML 4, the TARGET attribute value is case-insensitive, so that abc and ABC both refer to the same frame/window, and _top and _TOP both have the same meaning. However, most browsers treat the TARGET attribute value as case-sensitive and do not recognize ABC as being the same as abc, or _TOP as having the special meaning of _top.
    Also, some browsers include a security feature that prevents documents from being hijacked by third-party framesets. In these browsers, if a document’s link targets a frame defined by a frameset document that is located on a different server than the document itself, then the link opens in a new window instead.
 61. How do I make a frame with a vertical scrollbar but without a horizontal scrollbar?
      The only way to have a frame with a vertical scrollbar but without a horizontal scrollbar is to define the frame with SCROLLING=”auto” (the default), and to have content that does not require horizontal scrolling. There is no way to specify that a frame should have one scrollbar but not the other. Using SCROLLING=”yes” will force scrollbars in both directions (even when they aren’t needed), and using SCROLLING=”no” will inhibit all scrollbars (even when scrolling is necessary to access the frame’s content). There are no other values for the SCROLLING attribute.
62. Are there any problems with using frames?
      The fundamental problem with the design of frames is that framesets create states in the browser that are not addressable. Once any of the frames within a frameset changes from its default content, there is no longer a way to address the current state of the frameset. It is difficult to bookmark – and impossible to link or index – such a frameset state. It is impossible to reference such a frameset state in other media. When the sub-documents of such a frameset state are accessed directly, they appear without the context of the surrounding frameset. Basic browser functions (e.g., printing, moving forwards/backwards in the browser’s history) behave differently with framesets. Also, browsers cannot identify which frame should have focus, which affects scrolling, searching, and the use of keyboard shortcuts in general.
      Furthermore, frames focus on layout rather than on information structure, and many authors of framed sites neglect to provide useful alternative content in the NOFRAMES element. Both of these factors cause accessibility problems for browsers that differ significantly from the author’s expectations and for search engines.
63. How do I open a link into a new window?
      This feature is a byproduct of frames (In many opinions, the only good things frames did for web design). On any HTML page, you can just add target=”_blank” to your link syntax. e.g. yoursite.com

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