<?php
function limpia($var){
	$malo = array("\\","\'","'","%",";",":","&","#");
	$i=0;$o=count($malo);
	while($i<=$o){
		$var = str_replace($malo[$i],"",$var);
		$i++;
	}
	return $var;
}
 
function fncTime($tmpStart, $tmpEnd) {
	$expStart = explode(" ", $tmpStart); $intStart = $expStart[1].$expStart[0];
	$expEnd = explode(" ", $tmpEnd); $intEnd = $expEnd[1].$expEnd[0];
	return $intEnd-$intStart;
}
 
$string = "abcdefghijklmnñopkrstuvwkyz0123456789!\"#$%&'()*+,-./@?>=<;:";
 
$intStart = microtime(); $var =limpia($string); $intEnd = microtime();
echo "limpia() ".fncTime($intStart,$intEnd)."<br><br>";
 
$intStart = microtime(); $var = htmlentities($string, ENT_QUOTES); $intEnd = microtime();
echo "htmlentities() ".fncTime($intStart,$intEnd);
?>