HTML Text Links
A webpage can contain various links that take you directly to other pages and even specific parts of a given page. These links are known as hyperlinks.
Hyperlinks allow visitors to navigate between Web sites by clicking on words, phrases, and images. Thus you can create hyperlinks using text or images available on a webpage.
Note: I recommend to go through a short tutorial on Understanding URL
Linking Documents
A link is specified using HTML tag <a>. This tag is called anchor tag and anything between the opening <a> tag and the closing </a> tag becomes part of the link and a user can click that part to reach to the linked document. Following is the simple syntax to use <a> tag.
<a href="Document URL" ... attributes-list>Link Text</a>
Example
Let's try following example which links http://www.tutorialspoint.com at your page:
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
</head>
<body>
<p>Click following link</p>
<ahref="http://www.tutorialspoint.com" target="_self">Tutorials Point</a>
</body>
</html>
This will produce following result, where you can click on the link generated Tutorials Pointto reach to the home page of Tutorials Point.
Click following link
The target Attribute
We have used target attribute in our previous example. This attribute is used to specify the location where linked document is opened. Following are possible options:
Option
Description
_blank
Opens the linked document in a new window or tab.
_self
Opens the linked document in the same frame.
_parent
Opens the linked document in the parent frame.
_top
Opens the linked document in the full body of the window.
targetframe
Opens the linked document in a named targetframe.
Example
Try following example to understand basic difference in few options given for target attribute.
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
<basehref="http://www.tutorialspoint.com/">
</head>
<body>
<p>Click any of the following links</p>
<a href="/html/index.htm" target="_blank">Opens in New</a> |
<a href="/html/index.htm" target="_self">Opens in Self</a> |
<a href="/html/index.htm" target="_parent">Opens in Parent</a> |
<a href="/html/index.htm" target="_top">Opens in Body</a>
</body>
</html>
This will produce following result, where you can click on different links to understand the difference between various options given for target attribute.
Click any of the following links
Opens in New | Opens in Self | Opens in Parent| Opens in Body
Use of Base Path
When you link HTML documents related to the same website, it is not required to give a complete URL for every link. You can get rid of it if you use <base> tag in your HTML document header. This tag is used to give a base path for all the links. So your browser will concatenate given relative path to this base path and will make a complete URL.
Example
Following example makes use of <base> tag to specify base URL and later we can use relative path to all the links instead of giving complete URL for every link.
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
<basehref="http://www.tutorialspoint.com/">
</head>
<body>
<p>Click following link</p>
<a href="/html/index.htm" target="_blank">HTML Tutorial</a>
</body>
</html>
This will produce following result, where you can click on the link generated HTML Tutorialto reach to the HTML tutorial.
Now given URL <a href="/html/index.htm" is being considered as <ahref="http://www.tutorialspoint.com/html/index.htm".
Click following link
HTML Tutorial
Linking to a Page Section
You can create a link to a particular section of a given webpage by using name attribute. This is atwo step process.
First create a link to the place where you want to reach with-in a webpage and name it using <a...> tag as follows:
<h1>HTML Text Links <a name="top"></a></h1>
Second step is to create a hyperlink to link the document and place where you want to reach:
<ahref="/html/html_text_links.htm#top">Go to the Top</a>
This will produce following link, where you can click on the link generated Go to the Top to reach to the top of the HTML Text Link tutorial.
Go to the Top
Setting Link Colors
You can set colors of your links, active links and visited links using link, alink and vlinkattributes of <body> tag.
Example
Save the following in test.htm and open it in any web browser to see how link, alink and vlinkattributes work.
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
<basehref="http://www.tutorialspoint.com/">
</head>
<body alink="#54A250" link="#040404"vlink="#F40633">
<p>Click following link</p>
<a href="/html/index.htm" target="_blank" >HTML Tutorial</a>
</body>
</html>
This will produce following result. Just check color of the link before clicking on it, next check its color when you activate it and when the link has been visited.
Click following link
HTML Tutorial
Download Links
You can create text link to make your PDF, or DOC or ZIP files downloadable. This is very simple, you just need to give complete URL of the downloadable file as follows:
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
</head>
<ahref="http://www.sambhajikarad.info/page.pdf">Download PDF File</a>
</body>
</html>
This will produce following link and will be used to download a file.
Download PDF File
File Download Dialog Box
Sometimes it is desired that you want to give an option where a user will click a link and it will pop up a "File Download" box to the user in stead of displaying actual content. This is very easy and can be achieved using an HTTP header in your HTTP response.
For example, if you want make a FileName file downloadable from a given link then its syntax will be as follows.
#!/usr/bin/perl
# Addtional HTTP Header
print "Content-Type:application/octet-stream; name=\"FileName\"\r\n";
print "Content-Disposition:attachment; filename=\"FileName\"\r\n\n";
# Open the target file and list down its content as follows
open( FILE, "<FileName" );
while(read(FILE, $buffer, 100)){
print("$buffer");
}
Note: For more detail on PERL CGI programs, go through tutorial PERL and CGI.
ليست هناك تعليقات:
إرسال تعليق