JSトレーニング-ドラゴand Drop

	
This is a box.

window.onload = function(){
	var oDiv = document.getElementById("wrapper");
	var posX,posY;
	var listener = false;
	oDiv.onmousedown = function(e){
		e = e || window.event;
		listener = true;
		posX = e.clientX - parseInt(oDiv.offsetLeft);
		posY = e.clientY - parseInt(oDiv.offsetTop);
		return false;
		};
	document.onmousemove = function(e){
		e = e || window.event;
		if (listener == true){
			oDiv.style.left = e.clientX - posX + "px";
			oDiv.style.top = e.clientY - posY + "px";
		}
		return false;
		};
	document.οnmοuseup=function(){
		listener=false;
		};
	}