实现一个宽和高都是100像素的div可以用鼠标拖拽移动的效果

　　html,body{
width:100%;height:100%;margin:0px;padding:0px;
}
#box{
width:100px;height:100px;background:pink;position:absolute;
}

<div id="box"></div>

window.onload = function(){
var box = document.getElementById('box');
box.onmousedown = function(e){
var offsetX = e.offsetX;
var offsetY = e.offsetY;

document.body.onmousemove = function(e){
box.style.left = e.pageX-offsetX + 'px';
box.style.top = e.pageY-offsetY + 'px';
}
document.body.onmouseup = function(){
document.body.onmousemove = null;
document.body.onmouseup = null;
}
}
}