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Web Technologies-I
Notes 3.6.1 XML Style
Because of the advent of the eXtensible Markup Language (XML) and the migration of HTML to
an XML language (XHTML), the currently preferred technique for embedding PHP uses XML-
compliant tags to denote PHP instructions.
Coming up with tags to demark PHP commands in XML was easy, because XML allows the
definition of new tags. To use this style, surround your PHP code with <?php and ?>. Everything
between these markers is interpreted as PHP, and everything outside the markers is not. Although
it is not necessary to include spaces between the markers and the enclosed text, doing so improves
readability. For example, to get PHP to print “Hello, world”, you can insert the following line
in a web page:
<? php echo “Hello, world”; ?>
The trailing semicolon on the statement is optional, because the end of the block also forces the
end of the expression. Embedded in a complete HTML file, this looks like:
<! doctype html public “-//w3c//dtd html 4.0 transitional//en”>
<html>
<head>
<title>This is my first PHP program!</title>
</head>
<body>
<p> Look, ma! It is my first PHP program :< br />
<? php echo “Hello, world”; ?>
<br /> How cool is that? </p>
</body>
</html>
Of course, this is not very exciting—we could have done it without PHP. The real value of PHP
comes when we put dynamic information from sources such as databases and form values into
the web page. Let’s get back to our “Hello, world” example. When a user visits this page and
views its source, it looks like this:
<! doctype html public “-//w3c//dtd html 4.0 transitional//en”>
<html>
<head>
<title>This is my first PHP program!</title>
</head>
<body>
<p>
Look, ma! It is my first PHP program:<br /> Hello, world!<br /> How cool is that?
</p>
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