php实现验证邮箱地址的例子，很好的应用了php的正则。
1，html部分
<HTML>
<BODY>
<H2>php正则验证Email地址</H2>
<FORM METHOD="POST" ACTION="RegularExpressionTester.php">
<FONT FACE="Courier">
String:
<BR>
<INPUT TYPE="TEXT" NAME="string">
<BR><BR>
正则表达式:
<BR>
<INPUT TYPE="TEXT" SIZE=64 NAME="pattern"
VALUE="^([_a-zA-Z0-9-]+)@([a-zA-Z0-9-]+(.[a-zA-Z0-9-]+)*)$">
<BR><BR>
<BR>
<INPUT TYPE="SUBMIT">
</FONT>
</FORM>
</BODY>
</HTML>
2，php代码部分 RegularExpressionTester.php
<?php
echo "<BR><B>string:</B>$string";
echo "<BR><B>regular expression:</B> $pattern";
if (get_magic_quotes_gpc()){
echo "<BR><BR>";
echo "<BR>Stripping magic quotes....";
$string = stripslashes($string);
$pattern = stripslashes($pattern);
echo "<BR><B>string:</B> $string";
echo "<BR><B>regular expression:</B> $pattern";
}
$found = ereg($pattern, $string, $matches);
echo "<BR><BR>";
if ($found)
{
echo "<BR><B>验证:</B> 成功";
echo "<BR><BR>";
echo "<BR><B>Components: </B>";
for ($i = 0; $i < count($matches); $i++)
{
echo "<BR>$matches[$i]";
}
}
else
echo "<BR><B>验证:</B> 失败";
?>