本文实例讲述了JS实现的简易拖放效果。分享给大家供大家参考，具体如下：
<!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=gb2312" />
<title>简易拖放效果</title>
</head>
<body>
<script type="text/JavaScript">
<!--
var isIE = (document.all) ? true : false;// 是否ie
var $ = function (id) {
//返回id对象
return "string" == typeof id ? document.getElementById(id) : id;
};
var Class = {
// 带构造方法的类
create: function() {
return function() { this.initialize.apply(this, arguments); } //用apply应用下面的initialize初始化属性
}
}
var Extend = function(destination, source) {
//继承
for (var property in source) {
destination[property] = source[property];
}
}
var Bind = function(object, fun) {
return function() {
return fun.apply(object, arguments);
}
}
/**
用object对象调用fun参数是event||window event
**/
var BindAsEventListener = function(object, fun) {
return function(event) {
return fun.call(object, (event || window.event));
}
}
/**
添加帧听器事件
@oTarget 目标对象
@sEventType 事件类型
@fnHandler 目标触发事件对象
**/
function addEventHandler(oTarget, sEventType, fnHandler) {
if (oTarget.addEventListener) {
oTarget.addEventListener(sEventType, fnHandler, false);//firefox
} else if (oTarget.attachEvent) {
oTarget.attachEvent("on" + sEventType, fnHandler);//ie
} else {
oTarget["on" + sEventType] = fnHandler;//other
}
};
/**
清除添加的帧听器事件
@oTarget 目标对象
@sEventType 事件类型
@fnHandler 目标触发事件对象
**/
function removeEventHandler(oTarget, sEventType, fnHandler) {
if (oTarget.removeEventListener) {
oTarget.removeEventListener(sEventType, fnHandler, false);
} else if (oTarget.detachEvent) {
oTarget.detachEvent("on" + sEventType, fnHandler);
} else {
oTarget["on" + sEventType] = null;
}
};
/*------------------------------相关模型构造完毕-----------------------------------*/
//拖放程序
var SimpleDrag = Class.create();
SimpleDrag.prototype = {
//拖放对象,触发对象,初始化
initialize: function(drag) {
this.Drag = $(drag);
this._x = this._y = 0;
this._fM = BindAsEventListener(this, this.Move);//_fM方法就是应用MOVE方法参数是event||window.event
this._fS = Bind(this, this.Stop);//_fS类方法就是Stop方法
this.Drag.style.position = "absolute";
this.Drag.style.cursor = "move";
addEventHandler(this.Drag, "mousedown", BindAsEventListener(this, this.Start));
},
//准备拖动
Start: function(oEvent) {
this._x = oEvent.clientX - this.Drag.offsetLeft;
this._y = oEvent.clientY - this.Drag.offsetTop;
addEventHandler(document, "mousemove", this._fM);
addEventHandler(document, "mouseup", this._fS);
},
//拖动
Move: function(oEvent) {
this.Drag.style.left = oEvent.clientX - this._x + "px";
this.Drag.style.top = oEvent.clientY - this._y + "px";
},
//停止拖动
Stop: function() {
removeEventHandler(document, "mousemove", this._fM);
removeEventHandler(document, "mouseup", this._fS);
}
};
// -->
</script>
<div id="idDrag" style="border:5px solid #0000FF; background:#C4E3FD; width:50px; height:50px;"></div>
<script type="text/javascript">
<!--
new SimpleDrag("idDrag");
// -->
</script>
</body>
</html>
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希望本文所述对大家JavaScript程序设计有所帮助。
