function Counter(){
	// version: 0.1.0
	var targetArr 	= null;
	var intervalId 	= null;
	var interval 	= null;
	this.init();
}
Counter.prototype.init = function(){
	this.targetArr 	= new Array();
	this.interval 	= 1000; // one second
}

Counter.prototype.tick = function(){
	for(var i in this.targetArr){
		this.targetArr[i].currentValue = this.targetArr[i].currentValue + this.targetArr[i].valuePerIncrement;
		try{
			var targetElm = document.getElementById(this.targetArr[i].containerId);
			targetElm.innerHTML = this.numberFormat(Math.ceil(this.targetArr[i].currentValue), this.targetArr[i].numDecimal, '.', ',');
		}
		catch(e){
			// something went wrong	
		}
	}
}
Counter.prototype.start = function(){
	// does not work in IE, do not use
	try{
		for (var i in window) {
			if(window[i] == this){
				this.intervalId = setInterval(i+'.tick()', this.interval);
			}
		}
	}
	catch(e){
		// something went wrong	
	}
}
Counter.prototype.stop = function(){
	clearInterval(this.intervalId);	
}
Counter.prototype.setInterval = function(interval){
	this.interval = interval;
}
Counter.prototype.setIntervalId = function(intervalId){
	this.intervalId = intervalId;
}
Counter.prototype.add = function(startValue, valuePerIncrement, containerId, numDecimal){
	var newTarget 				= new Object();
	newTarget.currentValue 		= startValue;
	newTarget.valuePerIncrement = valuePerIncrement;
	newTarget.numDecimal 		= (numDecimal)?numDecimal:0;
	newTarget.containerId 		= containerId;
	this.targetArr.push(newTarget);
}
Counter.prototype.remove = function(containerId){
	var tempArr = new Array();
	for(var i in this.targetArr){
		if(this.targetArr[i].containerId != containerId){
			tempArr.push(this.targetArr[i]);
		}
	}
	this.targetArr = tempArr;
}
Counter.prototype.numberFormat = function(number, decimals, point, separator){
	point = point ? point : '.';
	number = number.toString().split('.');

	if(separator){
		var tmp_number = new Array();
		var negative = false;
		if(number[0] < 0){
			negative = true;
			number[0] = number[0].substring(1); // strip the - sign
		}
		
		for(var i = number[0].length, j = 0; i > 0; i -= 3){
			var pos = i > 0 ? i - 3 : i;
			tmp_number[j++] = number[0].substring(i, pos);
		}
		number[0] = tmp_number.reverse().join(separator);
		if(negative){
			number[0] = '-' + number[0];
		}
	}

	if(decimals){
		number[1] = number[1] ? number[1] : '0';
		var size = decimals - number[1].toString().length;
		if(size < 0){
			number[1] = number[1].substring(0, decimals);
		}
		else{
			for(var i = 0; i < size; i++)
				number[1] += '0';
		}
	}

	return(number.join(point));
}
Counter.prototype.getElementsByClassName = function (className, tag, elm){
	/*
		Developed by Robert Nyman, http://www.robertnyman.com
		Code/licensing: http://code.google.com/p/getelementsbyclassname/
	*/
	if (document.getElementsByClassName) {
		getElementsByClassName = function (className, tag, elm) {
			elm = elm || document;
			var elements = elm.getElementsByClassName(className),
				nodeName = (tag)? new RegExp("\\b" + tag + "\\b", "i") : null,
				returnElements = [],
				current;
			for(var i=0, il=elements.length; i<il; i+=1){
				current = elements[i];
				if(!nodeName || nodeName.test(current.nodeName)) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	else if (document.evaluate) {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = "",
				xhtmlNamespace = "http://www.w3.org/1999/xhtml",
				namespaceResolver = (document.documentElement.namespaceURI === xhtmlNamespace)? xhtmlNamespace : null,
				returnElements = [],
				elements,
				node;
			for(var j=0, jl=classes.length; j<jl; j+=1){
				classesToCheck += "[contains(concat(' ', @class, ' '), ' " + classes[j] + " ')]";
			}
			try	{
				elements = document.evaluate(".//" + tag + classesToCheck, elm, namespaceResolver, 0, null);
			}
			catch (e) {
				elements = document.evaluate(".//" + tag + classesToCheck, elm, null, 0, null);
			}
			while ((node = elements.iterateNext())) {
				returnElements.push(node);
			}
			return returnElements;
		};
	}
	else {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = [],
				elements = (tag === "*" && elm.all)? elm.all : elm.getElementsByTagName(tag),
				current,
				returnElements = [],
				match;
			for(var k=0, kl=classes.length; k<kl; k+=1){
				classesToCheck.push(new RegExp("(^|\\s)" + classes[k] + "(\\s|$)"));
			}
			for(var l=0, ll=elements.length; l<ll; l+=1){
				current = elements[l];
				match = false;
				for(var m=0, ml=classesToCheck.length; m<ml; m+=1){
					match = classesToCheck[m].test(current.className);
					if (!match) {
						break;
					}
				}
				if (match) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	return getElementsByClassName(className, tag, elm);
};