gistfile1.js

/*
*   Sugar for type detection working across frames and browsers ;)
*
*   Detected types
*
*       'arguments', 'array', 'boolean', 'date', 'document', 'element', 'error', 'fragment', 
*       'function', 'nodelist', 'null', 'number', 'object', 'regexp', 'string', 'textnode', 
*       'undefined', 'window'
*
*   Copyright (c) 2009 Daniel Steigerwald (http://daniel.steigerwald.cz), Mit Style License
*/
var $type = (function() {

    var toString = Object.prototype.toString,
        toStrings = {},
        nodeTypes = { 1: 'element', 3: 'textnode', 9: 'document', 11: 'fragment' },
        types = 'Arguments Array Boolean Date Document Element Error Fragment Function NodeList Null Number Object RegExp String TextNode Undefined Window'.split(' ');

    for (var i = types.length; i--; ) {
        var type = types[i], constructor = window[type];
        if (constructor) {
            try { toStrings[toString.call(new constructor)] = type.toLowerCase(); }
            catch (e) { }
        }
    }

    return function(item) {
        return item == null && (item === undefined ? 'undefined' : 'null') ||
            item.nodeType && nodeTypes[item.nodeType] ||
            typeof item.length == 'number' && (
                item.callee && 'arguments' ||
                item.alert && 'window' ||
                item.item && 'nodelist') ||
            toStrings[toString.call(item)];
    };

})();