本文实例讲述了php实现XSS安全过滤的方法。分享给大家供大家参考。具体如下：

function remove_xss($val) {  // remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed  // this prevents some character re-spacing such as <javascript>  // note that you have to handle splits with , , and 	 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 	, , and   $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]);)";        $pattern .= ")*";      }      $pattern .= $ra[$i][$j];     }     $pattern .= "/i";     $replacement = substr($ra[$i], 0, 2)."<x>".substr($ra[$i], 2); // add in <> to nerf the tag     $val = preg_replace($pattern, $replacement, $val); // filter out the hex tags     if ($val_before == $val) {      // no replacements were made, so exit the loop      $found = false;     }   }  }  return $val;}

希望本文所述对大家的php程序设计有所帮助。