Now that you've got the basics of PHP variables and operators down, the second article in this series takes a look at PHP's form-processing capabilities, and introduces you to the comparison and logical operators and the "if-else" and "switch" family of conditional statements.
As we've mentioned above, PHP4 introduces the new === operator to test whether variables are of the same type. Here's an example:
<?
if (!$submit)
{
// if $submit doesn't exist, it implies that the form
// has not yet been submitted
// so display the first page
?>
<html>
<head>
<style type="text/css">
td {font-family: Arial;}
</style>
</head>
<body>
<form method="GET" action="cookie.php4">
<table cellspacing="5" cellpadding="5" border="0>
<tr>
<td align="center">
Gimme something!
</td>
<td align="right">
<input type="text" name="yin">
</td>
</tr>
<tr>
<td align="center">
Gimme something else!
</td>
<td align="right">
<input type="text" name="yang">
</td>
</tr>
<tr>
<tr>
<td colspan="2" align="center">
<input type="submit" name="submit" value="Test!">
</td>
</tr>
</table>
</form>
</body>
</html>
<?
}
else
{
// if $submit does exist, the form has been submitted
// so process it
if ($yin === $yang)
{
$result = "Both variables are identical and of the same type";
}
else
{
$result = "The variables are either not identical or not of the same
type";
}
?>
<html>
<head>
<basefont face="Arial">
</head>
<body>
<b><? echo $result; ?></b>
</body>
</html>
<?
}
?>
Alternative syntax ------------------
PHP
also supports an alternative syntax for the various control structures discussed so far. For example, you could do this:
<?
if ($elvis == 0)
{
echo "Elvis has left the building!";
}
else
{
echo "Elvis is still backstage!";
}
?>
or you could do this
<?
if ($elvis == 0):
echo "Elvis has left the building!";
else:
echo "Elvis is still backstage!";
endif;
?>
The second alternative is equivalent to the first,
and simply involves replacing the first curly brace of every pair with a colon [:], removing the second curly brace, and ending the block with an "endif" statement.
And that's it for this week. Next time, we'll be bringing you loops, arrays and more forms - so make sure you don't miss it!
