实现思路：
①鼠标按下+鼠标移动 → 拖拽
②鼠标松开 → 无拖拽
③鼠标偏移 → 拖拽距离
用JavaScript事件方法表示就是：
① onmousedown + onmousemove → startDrag()
② onmouseup → stopDrag()
drag.js代码：
var params = {left: 0,
top: 0,
currentX: 0,
currentY: 0,
flag: false
}
//获取相关CSS属性
var getCss = function(o,key){
return o.currentStyle? o.currentStyle[key] : document.defaultView.getComputedStyle(o,false)[key]
}
//拖拽的实现
var startDrag = function(bar, target, callback){
if(getCss(target, "left") !== "auto"){
params.left = getCss(target, "left")
}
if(getCss(target, "top") !== "auto"){
params.top = getCss(target, "top")
}
//o是移动对象
bar.onmousedown = function(event){
params.flag = true
if(!event){
event = window.event
//防止IE文字选中
bar.onselectstart = function(){
return false
}
}
var e = event
params.currentX = e.clientX
params.currentY = e.clientY
}
document.onmouseup = function(){
params.flag = false
if(getCss(target, "left") !== "auto"){
params.left = getCss(target, "left")
}
if(getCss(target, "top") !== "auto"){
params.top = getCss(target, "top")
}
}
document.onmousemove = function(event){
var e = event ? event: window.event
if(params.flag){
var nowX = e.clientX, nowY = e.clientY
var disX = nowX - params.currentX, disY = nowY - params.currentY
target.style.left = parseInt(params.left) + disX + "px"
target.style.top = parseInt(params.top) + disY + "px"
}
if (typeof callback == "function") {
callback(parseInt(params.left) + disX, parseInt(params.top) + disY)
}
}
}
HTML/CSS
<style type="text/css">#box{position:absolute left:100px top:100px padding:5px background:#f0f3f9 font-size:12px -moz-box-shadow:2px 2px 4px #666666 -webkit-box-shadow:2px 2px 4px #666666}
#main{border:1px solid #a0b3d6 background:white}
#bar{line-height:24px background:#beceeb border-bottom:1px solid #a0b3d6 padding-left:5px cursor:move}
#content{width:420px height:250px padding:10px 5px}
</style>
<div id="box">
<div id="main">
<div id="bar">拖拽</div>
<div id="content">
内容……
</div>
</div>
</div>
JS部分
<script src="drag.js" type="text/javascript"></script><script type="text/javascript">
var oBox = document.getElementById("box")
var oBar = document.getElementById("bar")
startDrag(oBar, oBox)
</script>
我运行了你的代码，其实是可以复制粘贴的，因为你设置的复制出的图像覆盖了原来的位置了，这个可以查看元素可以看得到的。你可以改变if(Obj!=null)
{
Obj.style.left = event.x-Obj.l
Obj.style.top = event.y-Obj.t
}
改成
if(Obj!=null)
{
Obj.style.left = event.x-Obj.l+100+'px'
Obj.style.top = event.y-Obj.t+100+'px'
}
就可以看得出来了
见证奇迹的时刻到了：
<!DOCTYPE html><html>
<head>
<meta charset="UTF-8">
<style>
* {
margin: 0
padding: 0
}
.box {
position: absolute
top: 100px
left: 100px
}
/*四边*/
.box .t,
.box .b,
.box .l,
.box .r {
position: absolute
z-index: 1
background:#666
}
.box .l,
.box .r {
width: 10px
height: 100%
cursor: col-resize
}
.box .t,
.box .b {
width: 100%
height: 10px
cursor: row-resize
}
.box .t {
top: 0
}
.box .b {
bottom: 0
}
.box .l {
left: 0
}
.box .r {
right: 0
}
/*四角*/
.box .tl,
.box .bl,
.box .br,
.box .tr {
width: 20px
height: 20px
position: absolute
background: #CCC
z-index: 2
cursor: nwse-resize
}
.box .tl,
.box .bl {
left: -5px
}
.box .tr,
.box .br {
right: -5px
}
.box .br,
.box .bl {
bottom: -5px
}
.box .tl,
.box .tr {
top: -5px
}
.box .tr,
.box .bl {
cursor: nesw-resize
}
/*图片*/
img {
width: 100%
height: 100%
}
</style>
<script>
window.onload = function () {
var oDiv = document.getElementsByTagName('div')[0]
oDiv.style.width = '500px'
var aSpan = oDiv.getElementsByTagName('span')
for (var i = 0 i < aSpan.length i++) {
dragFn(aSpan[i])
}
function dragFn(obj) {
obj.onmousedown = function (ev) {
var oEv = ev || event
var oldWidth = oDiv.offsetWidth
var oldHeight = oDiv.offsetHeight
var oldX = oEv.clientX
var oldY = oEv.clientY
var oldLeft = oDiv.offsetLeft
var oldTop = oDiv.offsetTop
document.onmousemove = function (ev) {
var oEv = ev || event
if (obj.className == 'tl') {
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px'
oDiv.style.height=oldHeight-(oEv.clientY-oldY)+'px'
oDiv.style.left = oldLeft + (oEv.clientX - oldX) + 'px'
oDiv.style.top = oldTop + (oEv.clientY - oldY) + 'px'
}
else if (obj.className == 'bl') {
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px'
oDiv.style.height=oldHeight+(oEv.clientY-oldY)+'px'
oDiv.style.left = oldLeft + (oEv.clientX - oldX) + 'px'
oDiv.style.bottom = oldTop + (oEv.clientY + oldY) + 'px'
}
else if (obj.className == 'tr') {
oDiv.style.width = oldWidth + (oEv.clientX - oldX) + 'px'
oDiv.style.height = oldHeight - (oEv.clientY - oldY)+'px'
oDiv.style.right = oldLeft - (oEv.clientX - oldX) + 'px'
oDiv.style.top = oldTop + (oEv.clientY - oldY) + 'px'
}
else if (obj.className == 'br') {
oDiv.style.width = oldWidth + (oEv.clientX - oldX) + 'px'
oDiv.style.height = oldHeight + (oEv.clientY - oldY)+'px'
oDiv.style.right = oldLeft - (oEv.clientX - oldX) + 'px'
oDiv.style.bottom = oldTop + (oEv.clientY + oldY) + 'px'
}
else if (obj.className == 't') {
oDiv.style.height=oldHeight-(oEv.clientY-oldY)+'px'
oDiv.style.top = oldTop + (oEv.clientY - oldY) + 'px'
}
else if (obj.className == 'b') {
oDiv.style.height = oldHeight + (oEv.clientY - oldY)+'px'
oDiv.style.bottom = oldTop - (oEv.clientY + oldY) + 'px'
}
else if (obj.className == 'l') {
oDiv.style.height = oldHeight + 'px'
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px'
oDiv.style.left = oldLeft + (oEv.clientX - oldX) + 'px'
}
else if (obj.className == 'r') {
oDiv.style.height = oldHeight + 'px'
oDiv.style.width = oldWidth + (oEv.clientX - oldX) + 'px'
oDiv.style.right = oldLeft - (oEv.clientX - oldX) + 'px'
}
}
document.onmouseup = function () {
document.onmousemove = null
}
return false
}
}
}
</script>
</head>
<body>
<div class="box">
<span class="r"></span>
<span class="l"></span>
<span class="t"></span>
<span class="b"></span>
<span class="br"></span>
<span class="bl"></span>
<span class="tr"></span>
<span class="tl"></span>
<img src="https://gss0.bdstatic.com/70cFsjip0QIZ8tyhnq/img/iknow/730-350-0.jpg">
</div>
</body>
</html>
