/*
 * jQuery hash plugin used for storage hash name-value pairs
 * into browser locaiton's hash string.
 *
 * You can set or save hash name-value
 * @ $.hash("name", "value);
 *
 * You can get hash name's value
 * @ $.hash("name");
 *
 * You can delete hash name-value pairs
 * @ $hash("name", null);
 */

;(function($) {

if ($.hash) {
	return;
}

$.hash = function(name, value) {
	// jQuery doesn't support a is string judgement, so I made it by myself.
	function isString(obj) {
		return typeof obj == "string" || Object.prototype.toString.call(obj) === "[object String]";
	}
	if (!isString(name) || name == "") {
		return;
	}

	var clearReg = new RegExp("(&" + name + "=[^&]*)|(\\b" + name + "=[^&]*&)|(\\b" + name + "=[^&]*)", "ig");
	var getReg   = new RegExp("&*\\b" + name + "=[^&]*", "i");
	if (isString(value) && value !== "") {
		// clear all relative name-value pairs 
		var temp = location.hash.replace(clearReg, "");

		// build a new hash value-pair to save it
		temp += ((temp.indexOf("=") != -1) ? "&" : "") + name + "=" + encodeURIComponent(value);
		location.hash = temp;
	}
	else if (typeof value == "undefined") {
		// get name-value pair's value
		var result = location.hash.match(getReg);
		return result ? decodeURIComponent($.trim(result[0].split("=")[1])) : null;
	}
	else if (value === null) {
		// remove a specific name-value pair
		location.hash = location.hash.replace(clearReg, "");
	}
};

})(jQuery);