拖拽原理
- 鼠标和Div的相对距离不变
- 三大事件
- 把拖拽加到document上
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<style>
#div1 {width: 100px; height: 100px; background: red; position: absolute;}
</style>
<script>
window.onload = function() {
/*
onmousedown : 选择元素
onmousemove : 移动元素
onmouseup : 释放元素
*/
var oDiv = document.getElementById(‘div1‘);
oDiv.onmousedown = function(ev) {
var ev = ev || event;
var disX = ev.clientX - this.offsetLeft;
var disY = ev.clientY - this.offsetTop;
document.onmousemove = function(ev) {
var ev = ev || event;
oDiv.style.left = ev.clientX - disX + ‘px‘;
oDiv.style.top = ev.clientY - disY + ‘px‘;
}
document.onmouseup = function() {
document.onmousemove = document.onmouseup = null;
}
}
}
</script>
</head>
<body>
<div id="div1"></div>
<div style="width: 100px; height: 100px; background: green; position: absolute; left: 400px; top: 200px;"></div>
</body>
</html>