HTML Interview Questions And Answers _ 4

[sams.raghu]

HTML Interview Questions And Answers

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.
Unlike normal submit buttons (which return a name=value pair), the image input type returns the x-y coordinates of the location where the user clicked on the image. The browser returns the x-y coordinates as name.x=000 and name.y=000 pairs.
For compatability with various non-graphical browsing environments, the VALUE and ALT attributes should be set to the same value as the NAME attribute. For example:
<input type="image" name="Send" alt="Send" value="Send" src="send-button.gif">
For the reset button, one could use <button type="reset" ...>, JavaScript, and/or style sheets, although none of these mechanisms work universally.

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.

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.

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.

In theory these representations are equally valid. In practice, authoring convenience and limited support by browsers complicate the issue.

HTTP being a guaranteed "8-bit clean" protocol, you can safely send out 8-bit or multibyte coded characters, in the various codings that are supported by browsers.
A. HTML 2.0/3.2 (Latin-1)

By now there seems no convincing reason to choose &entityname; versus &#number;, so use whichever is convenient.
If you can confidently handle 8-bit-coded characters this is fine too, probably preferred for writing heavily-accented languages. Take care if authoring on non-ISO-8859-based platforms such as Mac, Psion, IBM mainframes etc., that your upload technique delivers a correctly coded document to the server. Using &amp;-representations avoids such problems.
B. A single repertoire other than Latin-1

In such codings as ISO-8859-7 Greek, koi8-r Russian Cyrillic, and Chinese, Japanese and Korean (CJK) codings, use of coded characters is the most widely supported and used technique.

Although not covered by HTML 3.2, browsers have supported this quite widely for some time now; it is a valid option within the HTML 4 specifications--use a validator such as the WDG HTML Validator or the W3C HTML Validation Service which supports HTML 4 and understands different character encodings.

Browser support for coded characters may depend on configuration and font resources. In some cases, additional programs called "helpers" or "add-ins" supply virtual fonts to browsers.

"Add-in" programs have in the past been used to support numeric references to 15-bit or 16-bit code protocols such as Chinese Big5 or Chinese GB2312.

In theory you should be able to include not only coded characters but also Unicode numeric character references, but browser support is generally poor. Numeric references to the "charset-specified" encoding may appear to produce the desired characters on some browsers, but this is wrong behavior and should not be used. Character entities are also problematical, aside from the HTML-significant characters <, &amp; etc.

C. Internationalization per HTML 4

Recent versions of the popular browsers have support for some of these features, but at time of writing it seems unwise to rely on this when authoring for a general audience.

Is there a way to prevent getting framed?
"Getting framed" refers to having your documents displayed within someone else's frameset without your permission. This can happen accidentally (the frameset author forgot to use TARGET="_top" when linking to your document) or intentionally (the frameset author wanted to display your content with his/her own navigation or banner frames).

To avoid "framing" other people's documents, you must add TARGET="_top" to all links that lead to documents outside your intended scope.
Unfortunately, there is no reliable way to specify that a particular document should be displayed in the full browser window, rather than in the current frame. One workaround is to use <BASE TARGET="_top"> in the document, but this only specifies the default target frame for links in the current document, not for the document itself.

If the reader's browser has JavaScript enabled, the following script will automatically remove any existing framesets:
<script type="text/javascript">
if (top.frames.length!=0) {
if (window.location.href.replace)
top.location.replace(self.location.href);
else
top.location.href=self.document.href;
}
</script>

An alternative script is

<script type="text/javascript">
function breakOut() {
if (self != top)
window.open("my URL","_top","");
}
</script>
</HEAD>
<BODY onLoad="breakOut()">