//安全过滤输入[jb]
function check_str($string, $isurl = false)
{
$string = preg_replace('/[\\x00-\\x08\\x0B\\x0C\\x0E-\\x1F]/','',$string);
$string = str_replace(array("\0","%00","\r"),'',$string);
empty($isurl) && $string = preg_replace("/&(?!(#[0-9]+|[a-z]+);)/si",'&',$string);
$string = str_replace(array("%3C",'<'),'<',$string);
$string = str_replace(array("%3E",'>'),'>',$string);
$string = str_replace(array('"',"'","\t",' '),array('"',''',' ',' '),$string);
return trim($string);
}