Simple (non-secure) hash function for JavaScript? [duplicate]

Possible Duplicate:
Generate a Hash from string in Javascript/jQuery

Can anyone suggest a simple (i.e. tens of lines of code, not hundreds of lines) hash function written in (browser-compatible) JavaScript? Ideally I'd like something that, when passed a string as input, produces something similar to the 32 character hexadecimal string that's the typical output of MD5, SHA1, etc. It doesn't have to be cryptographically secure, just reasonably resistant to collisions. (My initial use case is URLs, but I'll probably want to use it on other strings in the future.)

I didn't verify this myself, but you can look at this JavaScript implementation of Java's String.hashCode() method. Seems reasonably short.

With this prototype you can simply call .hashCode() on any string, e.g. "some string".hashCode(), and receive a numerical hash code (more specifically, a Java equivalent) such as 1395333309.

String.prototype.hashCode = function() {
    var hash = 0;
    for (var i = 0; i < this.length; i++) {
        var char = this.charCodeAt(i);
        hash = ((hash<<5)-hash)+char;
        hash = hash & hash; // Convert to 32bit integer
    }
    return hash;
}

There are many realizations of hash functions written in JS. For example:

• SHA-1: http://www.webtoolkit.info/javascript-sha1.html
• SHA-256: http://www.webtoolkit.info/javascript-sha256.html
• MD5: http://www.webtoolkit.info/javascript-md5.html

If you don't need security, you can also use base64 which is not hash-function, has not fixed output and could be simply decoded by user, but looks more lightweight and could be used for hide values: http://www.webtoolkit.info/javascript-base64.html