分析php过滤XSS攻击的函数

　　本文分享一例防范XSS攻击的php函数代码，学习下在php中防范XSS攻击的方法，有需要的'朋友参考学习下。

　　本节内容：

　　过滤XSS攻击

　　以下函数：

　　过滤用户的输入，保证输入是XSS安全的。

　　例子：

　　复制代码代码示例:

　　<?php

　　/**

　　* 过滤XSS攻击

　　* edit: www.jbxue.com

　　function RemoveXSS($val) {

　　// remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed

　　// this prevents some character re-spacing such as <java\0script>

　　// note that you have to handle splits with \n, \r, and \t later since they *are* allowed in some inputs

　　$val = preg_replace('/([\x00-\x08,\x0b-\x0c,\x0e-\x19])/', '', $val);

　　// straight replacements, the user should never need these since they're normal characters

　　// this prevents like <IMG SRC=@avascript:alert('XSS')>

　　$search = 'abcdefghijklmnopqrstuvwxyz';

　　$search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';

　　$search .= '1234567890!@#$%^&*()';

　　$search .= '~`";:?+/={}[]-_|\'\\';

　　for ($i = 0; $i < strlen($search); $i++) {

　　// ;? matches the ;, which is optional

　　// 0{0,7} matches any padded zeros, which are optional and go up to 8 chars

　　// @ @ search for the hex values

　　$val = preg_replace('/(&#[xX]0{0,8}'.dechex(ord($search[$i])).';?)/i', $search[$i], $val); // with a ;

　　// @ @ 0{0,7} matches '0' zero to seven times

　　$val = preg_replace('/(?{0,8}'.ord($search[$i]).';?)/', $search[$i], $val); // with a ;

　　}

　　// now the only remaining whitespace attacks are \t, \n, and \r

　　$ra1 = Array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed', 'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base');

　　$ra2 = Array('onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut', 'onbeforedeactivate', 'onbeforeeditfocus', 'onbeforepaste', 'onbeforeprint', 'onbeforeunload', 'onbeforeupdate', 'onblur', 'onbounce', 'oncellchange', 'onchange', 'onclick', 'oncontextmenu', 'oncontrolselect', 'oncopy', 'oncut', 'ondataavailable', 'ondatasetchanged', 'ondatasetcomplete', 'ondblclick', 'ondeactivate', 'ondrag', 'ondragend', 'ondragenter', 'ondragleave', 'ondragover', 'ondragstart', 'ondrop', 'onerror', 'onerrorupdate', 'onfilterchange', 'onfinish', 'onfocus', 'onfocusin', 'onfocusout', 'onhelp', 'onkeydown', 'onkeypress', 'onkeyup', 'onlayoutcomplete', 'onload', 'onlosecapture', 'onmousedown', 'onmouseenter', 'onmouseleave', 'onmousemove', 'onmouseout', 'onmouseover', 'onmouseup', 'onmousewheel', 'onmove', 'onmoveend', 'onmovestart', 'onpaste', 'onpropertychange', 'onreadystatechange', 'onreset', 'onresize', 'onresizeend', 'onresizestart', 'onrowenter', 'onrowexit', 'onrowsdelete', 'onrowsinserted', 'onscroll', 'onselect', 'onselectionchange', 'onselectstart', 'onstart', 'onstop', 'onsubmit', 'onunload');

　　$ra = array_merge($ra1, $ra2);

　　$found = true; // keep replacing as long as the previous round replaced something

　　while ($found == true) {

　　$val_before = $val;

　　for ($i = 0; $i < sizeof($ra); $i++) {

　　$pattern = '/';

　　for ($j = 0; $j < strlen($ra[$i]); $j++) {

　　if ($j > 0) {

　　$pattern .= '(';

　　$pattern .= '(&#[xX]0{0,8}([9ab]);)';

　　$pattern .= '|';

　　$pattern .= '|(?{0,8}([9|10|13]);)';