<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
.draggable {
200px;
height: 200px;
}
</style>
</head>
<body>
<div class="draggable" style="position: absolute;background: red;" id="myDiv"></div>
<p id="status"></p>
<script type="text/javascript">
function EventTarget() {
this.handlers = {};
}
EventTarget.prototype = {
constructor: EventTarget,
addHandler: function(type, handler) {
if (typeof this.handlers[type] == "undefined") {
this.handlers[type] = [];
}
this.handlers[type].push(handler);
},
fire: function(event) {
if (!event.target) {
event.target = this;
}
if (this.handlers[event.type] instanceof Array) {
var handlers = this.handlers[event.type];
for (var i = 0, len = handlers.length; i < len; i++) {
handlers[i](event);
}
}
},
removeHandler: function(type, handler) {
if (this.handlers[type] instanceof Array) {
var handlers = this.handlers[type];
for (var i = 0, len = handlers.length; i < len; i++) {
if (handlers[i] === handler) {
break;
}
}
handlers.splice(i, 1);
}
}
};
var EventUtil = {
addHandler: function(element, type, handler) { //添加事件
if (element.addEventListener) {
element.addEventListener(type, handler, false); //使用DOM2级方法添加事件
} else if (element.attachEvent) { //使用IE方法添加事件
element.attachEvent("on" + type, handler);
} else {
element["on" + type] = handler; //使用DOM0级方法添加事件
}
},
removeHandler: function(element, type, handler) { //取消事件
if (element.removeEventListener) {
element.removeEventListener(type, handler, false);
} else if (element.detachEvent) {
element.detachEvent("on" + type, handler);
} else {
element["on" + type] = null;
}
},
getEvent: function(event) { //使用这个方法跨浏览器取得event对象
return event ? event : window.event;
},
getTarget: function(event) { //返回事件的实际目标
return event.target || event.srcElement;
},
preventDefault: function(event) { //阻止事件的默认行为
if (event.preventDefault) {
event.preventDefault();
} else {
event.returnValue = false;
}
},
stopPropagation: function(event) { //立即停止事件在DOM中的传播
//避免触发注册在document.body上面的事件处理程序
if (event.stopPropagation) {
event.stopPropagation();
} else {
event.cancelBubble = true;
}
},
getRelatedTarget: function(event) { //获取mouseover和mouseout相关元素
if (event.relatedTarget) {
return event.relatedTarget;
} else if (event.toElement) { //兼容IE8-
return event.toElement;
} else if (event.formElement) {
return event.formElement;
} else {
return null;
}
},
getButton: function(event) { //获取mousedown或mouseup按下或释放的按钮是鼠标中的哪一个
if (document.implementation.hasFeature("MouseEvents", "2.0")) {
return event.button;
} else {
switch (event.button) { //将IE模型下的button属性映射为DOM模型下的button属性
case 0:
case 1:
case 3:
case 5:
case 7:
return 0; //按下的是鼠标主按钮（一般是左键）
case 2:
case 6:
return 2; //按下的是中间的鼠标按钮
case 4:
return 1; //鼠标次按钮（一般是右键）
}
}
},
getWheelDelta: function(event) { //获取表示鼠标滚轮滚动方向的数值
if (event.wheelDelta) {
return event.wheelDelta;
} else {
return -event.detail * 40;
}
},
getCharCode: function(event) { //以跨浏览器取得相同的字符编码，需在keypress事件中使用
if (typeof event.charCode == "number") {
return event.charCode;
} else {
return event.keyCode;
}
}
};
var DragDrop = function() {
var dragging = null,
diffX = 0,
diffY = 0,
dragdrop = new EventTarget();
function handleEvent(event) {
// 获取事件和目标
event = EventUtil.getEvent(event);
var target = EventUtil.getTarget(event);
// 确定事件类型
switch (event.type) {
case "mousedown":
if (target.className.indexOf("draggable") > -1) {
dragging = target;
diffX = event.clientX - target.offsetLeft;
diffY = event.clientY - target.offsetTop;
dragdrop.fire({
type: "dragstart",
target: dragging,
x: event.clientX,
y: event.clientY
});
}
break;
case "mousemove":
if (dragging !== null) {
// 指定位置
dragging.style.left = (event.clientX - diffX) + "px";
dragging.style.top = (event.clientY - diffY) + "px";
// 触发自定义事件
dragdrop.fire({
type: "drag",
target: dragging,
x: event.clientX,
y: event.clientY
});
}
break;
case "mouseup":
dragdrop.fire({
type: "dragend",
target: dragging,
x: event.clientX,
y: event.clientY
});
dragging = null;
break;
}
}
// 公共接口
dragdrop.enable = function() {
EventUtil.addHandler(document, "mousedown", handleEvent);
EventUtil.addHandler(document, "mousemove", handleEvent);
EventUtil.addHandler(document, "mouseup", handleEvent);
};
dragdrop.disable = function() {
EventUtil.removeHandler(document, "mousedown", handleEvent);
EventUtil.removeHandler(document, "mousemove", handleEvent);
EventUtil.removeHandler(document, "mouseup", handleEvent);
};
return dragdrop;
}();
DragDrop.addHandler("dragstart", function(event) {
var status = document.getElementById("status");
status.innerHTML = "Started dragging " + event.target.id;
});
DragDrop.addHandler("drag", function(event) {
var status = document.getElementById("status");
status.innerHTML = "<br/> Dragged " + event.target.id + " to (" + event.x + "," + event.y + ")";
});
DragDrop.addHandler("dragend", function(event) {
var status = document.getElementById("status");
status.innerHTML = "<br/> Dragged " + event.target.id + " to (" + event.x + "," + event.y + ")";
});
DragDrop.enable();
</script>
</body>
</html>