每天一个JavaScript实例-操作元素定位元素 

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>每天一个JavaScript实例-操作元素定位元素</title>
<style>
	div#a{
		width:500px;
	}
	div{
		border:1px solid #000;
		padding:10px;
	}
	#cursor{
		position:absolute;
		background-color:#ff0;
		width:20px;
		height:20px;
		left:50px;
		top:300px;
	}
</style>
<script>
function positionObject(obj){
	var rect  = obj.getBoundingClientRect();
	return [rect.left,rect.top];
}
window.onload = function(){
	var tst = document.documentElement.getBoundingClientRect();
	alert(tst.top);
	var cont = 'A';
	var cursor = document.getElementById("cursor");
	while(cont){
		cont = prompt("where do you want to move the cursor block?
","A");
		if(cont){
			cont = cont.toLowerCase();
			if(cont == "a"||cont=="b"||cont=="c"){
				var elem = document.getElementById(cont);
				var pos = positionObject(elem);
				console.log(pos);
				cursor.setAttribute("style","top:"+pos[1]+"px;"+"left:"+pos[0]+"px");
			}
		}

	}
}
</script>
</head>

<body>

<div id = "a">
<p>A</p>
<div id ="b">
	<p>B</p>
	<div id="c">
		<p>C</p>
	</div>
</div>
</div>
<div id="cursor">
	
</div>
</body>
</html>

posted @ 2017-07-10 14:49  zhchoutai  阅读(220)  评论(0)    收藏  举报