本文实例讲述了JavaScript实现可拖拽的拖动层Div。分享给大家供大家参考。具体如下：
这是一个完美的JS拖拽效果，带拖尾的JavaScript拖动层代码，经过了多次优化修正，复制节点的方法不错，值得JS爱好者学习，同时代码修正了给拖拽元素加ondblclick事件无效的问题，兼容多种浏览器，拷贝代码即可运行使用。
运行效果如下图所示：
具体代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
*{ margin:0; padding:0;} .div{ width:100px; height:100px; position:absolute;left:100px; top:100px; background:#ccc;}
</style>
</head>
<body>
<div class="div">
</div>
<script type="text/javascript">
var div = document.getElementsByTagName('div')[0];
var zIndex = 6;
drag(div);
div.ondblclick = function() {
alert("ok");
};
function drag(oDrag) {
var disX = dixY = 0;
oDrag.onmousedown = function(event) {
var event = event || window.event;
disX = event.clientX - this.offsetLeft;
disY = event.clientY - this.offsetTop;
var oTemp = this.cloneNode(true);
document.body.appendChild(oTemp);
document.onmousemove = function(event) {
var event = event || window.event;
var iL = event.clientX - disX;
var iT = event.clientY - disY;
var maxL = document.documentElement.clientWidth - oDrag.offsetWidth;
var maxT = document.documentElement.clientHeight - oDrag.offsetHeight;
iL <= 0 && (iL = 0);
iT <= 0 && (iT = 0);
iL >= maxL && (iL = maxL);
iT >= maxT && (iT = maxT);
oTemp.style.zIndex = zIndex++;
oTemp.style.opacity = "0.5";
oTemp.style.filter = "alpha(opacity=50)";
oTemp.style.left = iL + "px";
oTemp.style.top = iT + "px";
return false;
};
document.onmouseup = function() {
document.onmousemove = null;
document.onmouseup = null;
oDrag.style.opacity = oTemp.style.opacity;
var arr = {
left: oTemp.offsetLeft,
top: oTemp.offsetTop
};
oDrag.style.zIndex = oTemp.style.zIndex;
oAnimate(oDrag, arr, 300,
function() {
document.body.removeChild(oTemp);
});
oDrag.releaseCapture && oDrag.releaseCapture()
};
this.setCapture && this.setCapture();
return false
}
}
function oAnimate(obj, params, time, handler) {
var node = typeof obj == "string" ? $(obj) : obj;
var _style = node.currentStyle ? node.currentStyle: window.getComputedStyle(node, null);
var handleFlag = true;
for (var p in params) { (function() {
var n = p;
if (n == "left" || n == "top") {
var _old = parseInt(_style[n]);
var _new = parseInt(params[n]);
var _length = 0,
_tt = 10;
if (!isNaN(_old)) {
var count = _old;
var length = _old <= _new ? (_new - _old) : (_old - _new);
var speed = length / time * _tt;
var flag = 0;
var anim = setInterval(function() {
node.style[n] = count + "px";
count = _old <= _new ? count + speed: count - speed;
flag += _tt;
if (flag >= time) {
node.style[n] = _new + "px";
clearInterval(anim);
if (handleFlag) {
handler();
handleFlag = false;
}
}
},
_tt);
}
}
})();
}
}
</script>
</body>
</html>
希望本文所述对大家的javascript程序设计有所帮助。
