拖动问题,好奇怪啊!!!
html代码如下:
<html>
<head>
<title>Show Mouse Coordinates</title>
<script language="javascript">
document.onmousemove = mouseMove;
document.onmouseup   = mouseUp;
var dragObject  = null;
var mouseOffset = null;
function getMouseOffset(target, ev){
	ev = ev || window.event;
	var docPos    = getPosition(target);
	var mousePos  = mouseCoords(ev);
	return {x:mousePos.x - docPos.x, y:mousePos.y - docPos.y};
}
function getPosition(e){
	var left = 0;
	var top  = 0;
	while (e.offsetParent){
		left += e.offsetLeft;
		top  += e.offsetTop;
		e     = e.offsetParent;
	}
	left += e.offsetLeft;
	top  += e.offsetTop;
	return {x:left, y:top};
}
function mouseMove(ev){
	ev           = ev || window.event;
	var mousePos = mouseCoords(ev);
	if(dragObject){
		dragObject.style.position = 'absolute';
		dragObject.style.top      = mousePos.y - mouseOffset.y;
		dragObject.style.left     = mousePos.x - mouseOffset.x;
		return false;
	}
}
function mouseUp(){
	dragObject = null;
}
function makeDraggable(item){
	if(!item) return;
	item.onmousedown = function(ev){
		dragObject  = this;
		mouseOffset = getMouseOffset(this, ev);
		return false;
	}
}
function mouseCoords(ev){
	if(ev.pageX || ev.pageY){
		return {x:ev.pageX, y:ev.pageY};
	}
	return {
		x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,
		y:ev.clientY + document.body.scrollTop  - document.body.clientTop
	};
}
</script>
</head>
<body>
<div onmousedown="makeDraggable(this)" onmouseup="mouseUp();" onmousemove="mouseMove(this)" id="club">
<img src="club.gif"  />
</div>
</div>
</body>
</html>
问题是:当页面刷新第一次拖动的时候,不行!
当第二次拖动的时候,画面上的草花就可以动了!不明白为什么,问一下!
------解决方案--------------------
HTML code
<div onmousedown="makeDraggable(event,this)" onmouseup="mouseUp();" onmousemove="mouseMove(this)" id="club"> 
<img src="1.gif" /> 
</div>