Ignoring spaces and punctuation from palindrome script

I got the following script that checks if a phrase is Palindrome or not:

<script type="text/javascript" language="JavaScript">

function check(){
var x = isPalindrome(document.palinForm.inputWord.value);
document.palinForm.isPalin.value = x;
alert(x);
return true;
}

function isPalindrome(x) {
var rString = "";
var alen = x.length;
for (var i = alen ; i > 0 ; i--){
rString += x.charAt(i-1)
};
return (x == rString);
}
</script>


The problem is that it only works if the phrase has no spaces, comas, periods or even caps... for example: A man, a plan, a canal: Panama. would come out false because it's not in this order: amanaplanacanalpanama

how can I fix this?

 

Try this code

<script type="text/javascript" language="JavaScript">
function check(){
var x = isPalindrome(document.palinForm.inputWord.value);
document.palinForm.isPalin.value = x;
alert(x);
return true;
}

function isPalindrome(x) {
var rString = "";
var alen = x.length;
for (var i = alen ; i > 0 ; i--){
  if(alphanumeric(x.charAt(i-1))){
    rString += x.charAt(i-1)
  }
};

var nString = "";
for (var i = 0 ; i < alen ; i++){
  if(alphanumeric(x.charAt(i))){
    nString += x.charAt(i)
  }
};

return (nString.toLowerCase() == rString.toLowerCase());
}

function alphanumeric(alphane){
	var numaric = alphane;
	for(var j=0; j<numaric.length; j++){
	    var alphaa = numaric.charAt(j);
		var hh = alphaa.charCodeAt(0);
		if((hh > 47 && hh<58) || (hh > 64 && hh<91) || (hh > 96 && hh<123)){
		}
		else{
		    return false;
		}
 	}

 return true;
}

</script>

Code (markup):

 

or:

function isPalindrome(strX) {
	strX = strX.replace(/[^a-zA-Z0-9]+/g,"").toLowerCase();  //leave only alphanumeric chararacters, and convert to lower case.
	return(strX == strX.split("").reverse().join(""));  
}

Code (markup):