PHP(Hypertext Pre-processor: What is PHP?)>>
What is PHP?Hypertext Pre-processor (PHPs) is a
server-side scripting language, and server-sidescripts
are special commands you must place in Web pages. Those commands are processed
before the pages are sent from your Server to the Web browser of your visitor. A
typical PHP files will content commads to be executed in the server in
addition to the usual mixture of text and HTML (Hypertext Markup Language) tags.
When you type a URL in the Address box or click a link on a Web page,
you're asking a Web server on a computer somewhere to send a file to the Web
browser (sometimes called a "client") on your computer. If that file is a normal
HTML file, it looks exactly the same when your Web browser receives it as it did
before the Web server sent it. After receiving the file, your Web browser
displays its contents as a combination of text, images, and sounds. In the case
of an PHP page, the process is similar, except there's an extra processing step
that takes place just before the Web server sends the file. Before the Web
server sends the PHP file to the Web browser, it runs all server-side scripts
contained in the page. Some of these scripts display the current date, time, and
other information. Others process information the user has just typed into a
form, such as a page in the Web site's guestbook
To distinguish them from normal HTML pages, PHP files are usually given the
".php" extension.
What Can You Do with PHP?There are many things you can do with PHP.
- You can display date, time, and other information in different ways.
- You can make a survey form and ask people who visit your site to fill it
out, send emails, save the information to a file, etc
What Do PHP pages Look Like?The appearance of an PHP page depends on
who or what is viewing it. To the Web browser that receives it, an Active Server
Page looks just like a normal HTML page. If a visitor to your Web site views the
source code of an PHP page, that's what they see: a normal HTML page. However,
the file located in the server looks very different. In addition to text
and HTML tags, you also see server-side scripts. This is what the PHP page looks
like to the Web server before it is processed and sent in response to a request.
What Do PHP pages Look Like?Server-side scripts look a lot like HTML
tags. However, instead of starting and ending with lesser-than ( < ) and
greater-than ( > ) brackets, they typically start with <?php or <? and
will typically end with ?>. The <?php or <? are called anopening
tags, and the ?> is called a closing tag. In between these tags
are the server-side scripts. You can insert server-side scripts anywhere in your
Web page--even inside HTML tags.
Do You Have to Be a Programmer to Understand Server-Side
Scripting?There's a lot you can do with server-side scripts without
learning how to program. For this reason, much of the online Help for PHP is
written for people who are familiar with HTML but aren't computer
programmers.
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