Javascript String hash

string-hash.js

function stringHash(s) {
	var hash = 0,
	i = 0,
	char;
	if (s.length === 0) {
		return hash;
	}
	for (i = 0; i < s.length; i++) {
		char = s.charCodeAt(i);
		hash = 31*hash+char;
		hash = hash & hash;
	}
	return hash;
}