/* Client-side access to querystring name=value pairs
	Version 1.3
	28 May 2008
	
	License (Simplified BSD):
	http://adamv.com/dev/javascript/qslicense.txt
*/
function Querystring(qs) { // optionally pass a querystring to parse
	this.params = {};
	
	if (qs == null) qs = location.search.substring(1, location.search.length);
	if (qs.length == 0) return;

// Turn <plus> back to <space>
// See: http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13.4.1
	qs = qs.replace(/\+/g, ' ');
	var args = qs.split('&'); // parse out name/value pairs separated via &
	
// split out each name=value pair
	for (var i = 0; i < args.length; i++) {
		var pair = args[i].split('=');
		var name = decodeURIComponent(pair[0]);
		
		var value = (pair.length==2)
			? decodeURIComponent(pair[1])
			: name;
		
		this.params[name] = value;
	}
}

Querystring.prototype.get = function(key, default_) {
	var value = this.params[key];
	return (value != null) ? value : default_;
}

Querystring.prototype.contains = function(key) {
	var value = this.params[key];
	return (value != null);
}


/********************************************************************

API Reference

Constructor

new Querystring([querystring])

    Creates a new Querystring object, optionally passing a string qs
    to parse. If qs is omitted, the querystring from the current page
    is used.

    If querystring is passed, it should not begin with a "?".

    // Parse the current page's querystring
    var qs = new Querystring()

    // Parse a given querystring
    var qs2 = new Querystring("name1=value1&name2=value2")

Methods

qs.get(name[, default_value])

    Returns the value of querystring parameter name if it exists, or
    default_value if it doesn't.

    If default_value is omitted and parameter name doesn't exist, returns null.

    var v1 = qs2.get("name1")
    var v3 = qs2.get("name3", "default value")

    Note: If a name appears more than once in a querystring only the
    last value is kept.

qs.contains(name)

    Returns true if the querystring has a parameter name, else false.

    if (qs2.contains("name1")){ alert(qs2.get("name1"));}






*************************************************************************/