type.js

(function($){

	var toString = Object.prototype.toString;
	
	
	var class2type = {
		"[object Boolean]": "boolean",
		"[object Number]": "number",
		"[object String]": "string",
		"[object Function]": "function",
		"[object Array]": "array",
		"[object Date]": "date",
		"[object RegExp]": "regexp"
	};
	
	// First verion.
	$.typeA = function( obj ) {
		if ( !obj ) {
			return obj === null ? "null" : typeof obj;
		}
		
		return class2type[ toString.call( obj ) ] || "object";
	};

	// Maybe something faster reducing the need of toString.
	$.typeB = function( obj ) {
		var ret = typeof obj;
		
		if ( ret !== "object" ) {
			return ret;
		}
		
		if ( obj === null ) {
			return "null";
		}
		
		return class2type[ toString.call( obj ) ] || ret;
	};
	
	
	var rbuiltin = /^(?:Boolean|Number|String|Function|Array|Date|RegExp)$/;
	
	// For those who prefers regexps instead of maps.
	// Probably something slower on IE.
	$.typeC = function( obj ) {
		var ret = typeof obj;
		
		if ( ret !== "object" ) {
			return ret;
		}
		
		if ( obj === null ) {
			return "null";
		}
		
		ret = toString.call( obj ).slice(8, -1);
		return rbuiltin.test( ret ) ? ret.toLowerCase() : "object";
	};
	
})(jQuery || window);