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;
if (this.length == 0) {
return hash;
}
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;
}