本文介绍了一个经过优化的JavaScript拖动层类，旨在解决跨浏览器兼容性问题，特别是在IE和Firefox环境下的稳定运行。该类的核心改进在于增加了拖动过程中的半透明显示特效，提升了用户交互体验。文章提供了完整的代码实现，详细解析了鼠标事件监听、坐标计算及样式动态调整逻辑，适用于需要灵活拖拽功能的前端开发场景。
JS拖动层类实现与半透明特效
自己优化修改了网上的一个JS拖动类，增加了拖动时显示半透明的特效。 https://www.jb51.net/article/16122.htm 注意，本文类中的Cminfo类请 查看： https://www.jb51.net/article/18760.htm
具体实现代码如下：
//*********************************移动层 函数 开始*******************************************
//生成拖动层的方法十分简便，只需传入相应参数即可。若参数之一为数组，则代表局部拖动模式，其中数组的第一个元素arr[0]指定为可拖动的层，其余部分定义整体范围。
//实例化示例：new divDrag(['test'], [getObject('test31'),getObject('test3')], getObject('test1') ,getObject('test2') ,[getObject('test41'),getObject('test4')]);
//确保具有拖动属性的层在CSS中设置了position:absolute;样式。
Array.prototype.extend = function(C){for(var B=0,A=C.length;B<A;B++){this.push(C[B]);}return this;}
function divDrag()
{
var A,B,gCn;
var zIndex = 1;
this.dragStart = function(e)
{
e = e||window.event;
if((e.which && (e.which!=1))||(e.button && (e.button!=1))){return;}
var pos = this.gPos;
gCn = this.parent||this;
if(document.defaultView)
{
_top = document.defaultView.getComputedStyle(gCn,null).getPropertyValue("top");
_left = document.defaultView.getComputedStyle(gCn,null).getPropertyValue("left");
}
else
{
if(gCn.currentStyle)
{
_top = gCn.currentStyle["top"];
_left = gCn.currentStyle["left"];
}
}
pos.ox = (e.pageX||(e.clientX+document.documentElement.scrollLeft))-parseInt(_left);
pos.oy = (e.pageY||(e.clientY+document.documentElement.scrollTop))-parseInt(_top);
if(!!A)
{
if(document.removeEventListener)
{
document.removeEventListener("mousemove",A,false);
document.removeEventListener("mouseup",B,false);
}
else
{
document.detachEvent("onmousemove",A);
document.detachEvent("onmouseup",B);
}
}
A = this.dragMove.create(this);
B = this.dragEnd.create(this);
if(document.addEventListener)
{
document.addEventListener("mousemove",A,false);
document.addEventListener("mouseup",B,false);
}
else
{
document.attachEvent("onmousemove",A);
document.attachEvent("onmouseup",B);
}
gCn.style.zIndex = (++zIndex);
}
this.dragMove = function(e)
{
e = e||window.event;
var pos = this.gPos;
gCn = this.parent||this;
gCn.style.top = (e.pageY||(e.clientY+document.documentElement.scrollTop))-parseInt(pos.oy)+'px';
gCn.style.left = (e.pageX||(e.clientX+document.documentElement.scrollLeft))-parseInt(pos.ox)+'px';
try{if(CMInfo.Bs_Name=='IE'){gCn.style.filter = "alpha(opacity=70)";}else{gCn.style.opacity = "0.7";}}catch(e){}
this.stop(e);
}
this.dragEnd = function(e)
{
var pos = this.gPos;
e = e||window.event;
if((e.which && (e.which!=1))||(e.button && (e.button!=1))){return};
gCn = this.parent||this;
if(!!(this.parent)){this.style.backgroundColor = pos.color;}
try{if(CMInfo.Bs_Name=='IE'){gCn.style.filter = "alpha(opacity=100)";}else{gCn.style.opacity = 1;}}catch(e){}
if(document.removeEventListener)
{
document.removeEventListener("mousemove",A,false);
document.removeEventListener("mouseup",B,false);
}
else
{
document.detachEvent("onmousemove",A);
document.detachEvent("onmouseup",B);
}
A = null;
B = null;
gCn.style.zIndex = (++zIndex);
this.stop(e);
}
this.shiftColor = function()
{
this.style.backgroundColor="#EEEEEE";
}
this.position = function (e)
{
var t=e.offsetTop;
var l=e.offsetLeft;
while(e=e.offsetParent)
{
t += e.offsetTop;
l += e.offsetLeft;
}
return {x:l,y:t,ox:0,oy:0,color:null}
}
this.stop = function(e)
{
if(e.stopPropagation){e.stopPropagation();}else{e.cancelBubble=true;}
if(e.preventDefault){e.preventDefault();}else{e.returnValue=false;}
}
this.create = function(bind)
{
var B = this;
var A = bind;
return function(e){return B.apply(A,[e]);}
}
this.dragStart.create = this.create;
this.dragMove.create = this.create;
this.dragEnd.create = this.create;
this.shiftColor.create = this.create;
this.initialize = function()
{
for(var A=0,B=arguments.length;A<B;A++)
{
C=arguments[A];
if(!(C.push)){C = [C];}
gC = (typeof(C[0])=='object')?C[0]:(typeof(C[0])=='string'?getObject(C[0]):null);
if(!gC){continue};
gC.gPos = this.position(gC);
gC.dragMove = this.dragMove;
gC.dragEnd = this.dragEnd;
gC.stop = this.stop;
if(!!C[1])
{
gC.parent = C[1];
gC.gPos.color = gC.style.backgroundColor;
}
if(gC.addEventListener)
{
gC.addEventListener("mousedown",this.dragStart.create(gC),false);
if(!!C[1]){gC.addEventListener("mousedown",this.shiftColor.create(gC),false); }
}
else
{
gC.attachEvent("onmousedown",this.dragStart.create(gC));
if(!!C[1]){gC.attachEvent("onmousedown",this.shiftColor.create(gC));}
}
}
}
this.initialize.apply(this,arguments);
}
//*********************************移动层 函数 结束*******************************************