<?php

$list = array('ass', 'bitch', 'damn', 'fuck', 'shit'); //ARRAY OF WORDS TO CENSOR
$str = 'What the Fuck is that? You mothafuckin bitch!!!'; //STRING TO SEARCH THROUGH

//REPLACES EVERY WORD IN 'list' WITH THE FIRST LETTER AND ASTERICKS
for($i=0; $i<count($list); $i++){
    $c = $list[$i]; //WORD IN THE ARRAY
    $firstl = substr($c, 0, 1);    //FIRST LETTER
    $strlen = strlen($c); //NUMBER OF CHARACTER OF EACH WORD
    $astr = str_repeat('*', $strlen-1); //REPLACES THE REST OF WORD WITH ASTERICKS
    $censored = $firstl.$astr; //CENSORED WORD Ex: (f***)
    //USED TO PREVENT a (|ass|bitch) IN REGEX
    if($i==0){
    $d .= $c;
    } else {
    $d .= '|'.$c;
    }
    $str = eregi_replace('('.$d.')', $censored, $str); //CENSORING PROCESS HERE
}

echo $str;

?>

function censor(str){ //STRING VARIABLE FROM <input> TAG
var astericks = '****'; //ASTERICKS
var profanity = /^(S)*(ass|bitch|damn|fuck|shit)+(S)*$/gi; //ARRAY OF WORDS TO CENSOR
var s = ''; //BLANK VARIABLE UNTIL THE SECOND 'FOR LOOP'

var w = str.split(" "); //SPLITS EACH WORDS BY SPACES
var words = w.length; //THE NUMBER OF SPLIT
for(i=0; i<str.length; i++){
if(str.substr(i, 2)=="  "){ //BY DEFAULT, > 1 SPACES COUNT AS A WORD, THIS PREVENTS THE EXTRA
words--; //DECREASES THE NUMBER OF WORDS BY 1 IF THERE ARE > 1 SPACES IN A ROW
}
}

for(i=0; i<words; i++){
if(w[i].match(profanity)){ //CHECKS TO SEE IF WORDS MATCH ANY OF THE LIST
s += w[i][0]+astericks+' '; //IF SO, ADDS THE ASTERICKS TO EACH WORD FROM THE LIST
} else {
s += w[i]+' '; //JUST ADDS THE OTHER WORDS IN THE STRING
}
}

$("#censored").html(s); //DISPLAYED IN HTML
}
<input onKeyUp="censor(this.value)"><br>