php 判断是否存在恶意字符实例

function is_bad_chars($str){ 
    $bad_chars = array("",&#39; &#39;,"&#39;",&#39;"&#39;,&#39;/&#39;,&#39;*&#39;,&#39;,&#39;,&#39;<&#39;,&#39;>&#39;,"\r","\t","\n",&#39;$&#39;,&#39;(&#39;,&#39;)&#39;,&#39;%&#39;,&#39;+&#39;,&#39;?&#39;,&#39;;&#39;,&#39;^&#39;,&#39;#&#39;,&#39;:&#39;,&#39;　&#39;,&#39;`&#39;,&#39;=&#39;,&#39;|&#39;,&#39;-&#39;); 
    foreach($bad_chars as $value){ 
        if (strpos($str,$value) !== false){ 
            return true; 
        } 
    } 
}

function outip($ip){//排除ip 
    @$txt = file_get_contents("ip/ip.txt" ); 
    $txtarr = explode("\r\n" , trim($txt)); 
    if(count($txtarr)<0){ 
        return false; 
    } 
    if(in_array($ip,$txtarr)){ 
        return true; 
    }else{
        return false; 
    }
}