Set - 4

Question 1 :

How do I make a thumbnail for my image(s)? 

Answer :

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.

Here are the steps:
1. Load a copy of the image into your graphics editing program.
2. Determine the ratio the thumbnail to be. (Do you want it to be half the size? One third of the size? One quarter of the size? One tenth of the size?)
3. Find the resize (or change attributes) function of your program. Most programs will recogize a percentage, for example you can type in 25% for height and width if you want the thumbnail to be a quarter of the size. (It it doesn't do percentages, you can calculate it by multiplying the pixels by the percentage. If you have a graphic that is 400 by 100, and you want it 25% of the size, multiple each measurement by .25. In this case, you'll get 100 and 25.)
4. Once you are satisfied with the thumbnail, think of a name for the image. Choose Save As and enter that name. (Tip: I like to just add t after the image name. For taco.jpg I'd use tacot.jpg)
5. Upload the image to your site, and edit your HTML to load the new image name with the new, smaller size. If you wish, you can link to the larger image around the image.

Example: You have taco.jpg which is 400 pixels wide and 100 pixels high. You made a thumbnail of it called tacot.jpg, which is now 100 pixels wide and 25 pixels high. After you have both images uploaded, here's the code:

<a href="taco.jpg"><img src="tacot.jpg" width=100 height=25 border=0 alt="click for larger taco"></a>

You'll find border=0 to be helpful in eliminating a link-colored box around your thumbnail.


Question 2 :

What is the difference between the HTML form methods GET and POST?

Answer :

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 - httpargs


Question 3 :

How do I rename all the files from .htm to .html after copying them from a PC to a UNIX machine?

Answer :

UNIX's mv (`move') command won't handle wildcard filenames. However, there's a program called htmaddl (for `HTM-add-"L"'), so you can login and type htmaddl. This will rename all .htm files to .html

If you haven't got this program on your UNIX machine, you can type it into a file called htmaddl:

#! /bin/sh

for f in *.htm; do
base=`basename $f .htm`
mv $f $base.html
done

After saving it and exiting your editor, make it executable by typing the command

chmod ugo+x htmaddl
Best of all, move it into your ~/bin directory, or ask your WebMeister to put it in /usr/local/bin so everyone can use it.


Question 4 :

How do I put sounds for older versions of Internet Explorer?

Answer :

For older versions of Internet Explorer, this technique was used <BG SOUND="sound.ext">.


Question 5 :

Can I use any HTML in the box? 

Answer :

Yes. Any HTML tag that your browser supports will work in the box. So you can carry tags from chapters to chapters and mix and match...


Question 6 :

How to transferring user to new web page automatically?

Answer :

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.


Question 7 :

I'm trying to `include' a HTML document in another document...Is there a way to do this? 

Answer :

Yes, there are several ways to do this. But remember, HTML is not a programming language - it doesn't have `directives': it's a markup language, so trying to compare it to C or Pascal is not going to be very meaningful. 

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;

This is the General Entity mechanism used universally in normal SGML work and does exactly what is wanted, with the added benefit that you can have multiple occurrences of &foo; if you need to include some text at more than one place. Unfortunately none of the browsers except Panorama support it, basically because very few of the programmers who write browsers bothered to read up on what can be done.
* The second way is to use the facilities of your server. This has to be enabled by someone with access to the server configuration files (ask your WebMeister). For example, the NCSA server lets you embed a command inside an SGML comment:

<!--#exec cmd="cat myfile.html"-->

Provided this occurs in a file with a special file type (eg .shtml, and this is what has to be specified in the server configuration), the server will parse the file and send out the result of the command embedded in the document. 
* There is in fact a vastly easier way to do this. SGML provides a PI mechanism (Processing Instruction) in the form:

<?cat myfile>

SGML/HTML couldn't care what you put inside (except it must not, for obvious reasons, contain the `>' character!). This would be a great way to specify a page break, for example: suppose you were processing an SGML file using PostScript, you could say <p><?showpage></p>...but again, none of the browsers except Panorama support this, again because they guys who write them have never bothered to actually read up on how SGML works.


Question 8 :

How do I keep people from stealing my source code and/or images?

Answer :

Because copies of your HTML files and images are stored in cache, it is impossible to prevent someone from being able to save them onto their hard drive. If you are concerned about your images, you may wish to embed a watermark with your information into the image. Consult your image editing program's help file for more details.


Question 9 :

The colors on my page look different when viewed on a Mac and a PC.

Answer :

The Mac and the PC use slightly different color palettes. There is a 216 "browser safe" color palette that both platforms support; the Microsoft color picker page has some good information and links to other resources about this. In addition, the two platforms use different gamma (brightness) values, so a graphic that looks fine on the Mac may look too dark on the PC. The only way to address this problem is to tweak the brightness of your image so that it looks acceptable on both platforms.


Question 10 :

How do you create tabs or indents in Web pages?

Answer :

There was a tag proposed for HTML 3.0, but it was never adopted by any major browser and the draft specification has now expired. You can simulate a tab or indent in various ways, including using a transparent GIF, but none are quite as satisfactory or widely supported as an official tag would be.


Question 11 :

My page looks good on one browser, but not on another?

Answer :

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.


Question 12 :

How do I make sure my framed documents are displayed inside their frameset? 

Answer :

When the sub-documents of a frameset state are accessed directly, they appear without the context of the surrounding 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 

Note that in either case, you must have a separate frameset document for every content document. If you link to the default frameset document, then your reader will get the default content document, rather than the content document he/she was trying to access. These frameset documents should be generated automatically, to avoid the tedium and inaccuracy of creating them by hand. 
Note that you can work around the problem with bookmarking frameset states by linking to these separate frameset documents using TARGET="_top", rather than linking to the individual content documents.


Question 13 :

How do I update two frames at once? 

Answer :

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: 
<p><a href="URL1" target="Frame1" onClick="top.Frame2.location='URL2';"></p>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).


Question 14 :

Can I have two or more Submit buttons in the same form? 

Answer :

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">

Note that if you are using image submit buttons, you need to provide different NAME attributes for them too. Also, browser behavior can be inconsistent when the form is submitted without a submit button (e.g., by hitting ENTER). 
If you're unsure what results you're going to get when you submit your form, TipJar has a standard script which you can use. Code this, for example (assuming method "post"):

<form method="post" action="http://www.yoursite.com/cgi-bin/test">

and then go through the motions of submitting your form. The TipJar server decodes the form input, and displays the result to you.


Question 15 :

How do I make a link or form in one frame update another frame?

Answer :

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:

<p><a target="content" href=...> </p>
To target a form submission, use the TARGET attribute of the FORM element, like this:

<p><form target="content" action=...> </p>
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:

<p><base target="content"></p>


Question 16 :

When I try to upload my site, all my images are X's. How do I get them to load correctly?

Answer :

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.


Question 17 :

Is there a site that shows which tags work on which browsers?

Answer :

There have been several attempts to do this, but I'm not aware of any really good source of comparisons between the browsers. The trouble is that there are many different versions of each browser, and many different tags. All current browsers should support the tags in the official HTML 3.2 specification, but the major ones also support nonstandard tags and sometimes have slightly different implementations. One place that has fairly good compatibility info is Browsercaps.


Question 18 :

Why does the browser show my plain HTML source?

Answer :

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.


Question 19 :

How can I display an image on my page?

Answer :

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">

 


Question 20 :

Why do my links open new windows rather than update an existing frame?

Answer :

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.


Question 21 :

How do I get out of a frameset?

Answer :

If you are the author, this is easy. You only have to add the TARGET attribute to the link that takes readers to the intended 'outside' document. Give it the value of _top.
In many current browsers, it is not possible to display a frame in the full browser window, at least not very easily. The reader would need to copy the URL of the desired frame and then request that URL manually.
I would recommend that authors who want to offer readers this option add a link to the document itself in the document, with the TARGET attribute set to _top so the document displays in the full window if the link is followed.


Question 22 :

How do I make a frame with a vertical scrollbar but without a horizontal scrollbar?

Answer :

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.


Question 23 :

Are there any problems with using frames?

Answer :

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.


Question 24 :

Do search engines dislike frames?

Answer :

Search engines can link directly to framed content documents, but they cannot link to the combinations of frames for which those content documents were designed. This is the result of a fundamental flaw in the design of frames. 
Search engines try to provide their users with links to useful documents. Many framed content documents are difficult to use when accessed directly (outside their intended frameset), so there is little benefit if search engines offer links to them. Therefore, many search engines ignore frames completely and go about indexing more useful (non-framed) documents. 
Search engines will index your <NOFRAMES> content, and any content that is accessible via your