<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
#div1{
width: 100px;
height: 100px;
background: red;
position: absolute;
}
#img1{
position: absolute;
}
</style>
<script>
window.onload=function(){
var oDiv=document.getElementById("div1");
var oImg=document.getElementById("img1");
drag(oImg);
drag(oDiv);
function drag(obj){
obj.onmousedown = function(ev){
var ev = ev || event;
var disX = ev.clientX - this.offsetLeft;
var disY = ev.clientY - this.offsetTop;
if(obj.setCapture){
obj.setCapture();
}
document.onmousemove = function(ev){
var ev = ev || event;
var L = ev.clientX-disX;
var T = ev.clientY-disY;
if(L < 0){
L = 0; //可视区域的宽度-当前对象的宽度
}else if(L > document.documentElement.clientWidth - obj.offsetWidth){
L = document.documentElement.clientWidth - obj.offsetWidth
}
if(T < 0){
T = 0;
}else if(T > document.documentElement.clientHeight - obj.offsetHeight){
T = document.documentElement.clientHeight - obj.offsetHeight
}
obj.style.left = L + "px";
obj.style.top = T + "px";
}
document.onmouseup = function(){
document.onmousemove=document.onmouseup=null;
if(obj.releaseCapture){
obj.releaseCapture();
}
}
return false;
}
}
}
</script>
</head>
<body>
<div id="div1"></div>
<img src="img/1.jpg" id="img1" />
</body>
</html>
