Generate random GUIDs usable as element IDs (first character is always a letter)

guid.js

(function () {
    var S4 = function (n, d) {
        return (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1) + (n > 1 ? (d || '') + S4(n - 1, d) : '');
    };
    return (String.fromCharCode(97 + Math.floor(Math.random() * 26)) + S4().substring(1) + S4(5, '-') + S4(2));
})();