/*
Constructor:
    // 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]) 
        var v1 = qs2.get("name1")
        var v3 = qs2.get("name3", "default value")
    qs.contains(name) 
        if (qs2.contains("name1")){ alert(qs2.get("name1"));}
*/

function Querystring(qs) { // optionally pass a querystring to parse
	this.params = {};
	this.paramsName = new Array();
	
	if (qs == null) qs = location.search.substring(1, location.search.length);
	if (qs.length == 0) return;

    if(qs.substr(0,1)=='?') qs = qs.substr(1,qs.length-1);
    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;
		this.paramsName[i] = name;
	}
};
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);
};
Querystring.prototype.remove = function(key) {
	
	var paramsTMP = {};
	var paramsNameTMP = new Array();
	var index = 0;
    for (var i = 0; i < this.paramsName.length; i++) {
		if(this.paramsName[i].toLowerCase() != key.toLowerCase())
		{
		    var name = this.paramsName[i];
			paramsTMP[name] = this.params[name];
		    paramsNameTMP[index] = name;
		    index++;
		}
	}
	this.params = paramsTMP;
    this.paramsName = paramsNameTMP;
	return;
};
Querystring.prototype.getStringWithPrefix = function() {
	var sqs = '';
	var first = true;
	for (var i=0; i < this.paramsName.length; i++)
    {
        var p = this.paramsName[i];
        if(first)
        {
           first = false;
           sqs = "?" + p + "=" + this.get(p);
        }else
        {
           sqs += "&" + p + "=" + this.get(p);
        }
    }
	return sqs;
};
Querystring.prototype.getString = function() {
	var sqs = '';
	for (var i=0; i < this.paramsName.length; i++)
    {
        var p = this.paramsName[i];
        sqs += "&" + p + "=" + this.get(p);
    }
	return sqs;
};