一、EventUtil.js
具体可参考《EventUtil——跨浏览器的事件对象》 地址： https://www.cnblogs.com/hykun/p/EventUtil.html
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
}
}
}
二、自定义事件-- CustomEvent.js
/**
* 自定义事件
*/
function EventTarget() {
//储存事件处理程序
this.handlers = {}
}
EventTarget.prototype = {
constructor: EventTarget,
//注册给定类型事件的事件处理程序
addHandler: function(type, handler) {
if (typeof this.handlers[type] == 'undefined') {
this.handlers[type] = []
}
this.handlers[type].push(handler)
},
//用于触发一个事件
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)
}
}
},
//用于注销某个事件类型的事件处理程序
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)
}
}
}
三、 拖放事件 --- drag.js
var DragDrop = (function() {
var dragdrop = new EventTarget(),
dragging = null,
diffX = 0,
diffY = 0
function handleEvent(event) {
//获取事件和对象
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
})()
四、 html文件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script src="./EventUtil.js"></script>
<script src="./CustomEvent.js"></script>
<script src="./drag.js"></script>
<title>Document</title>
<style>
#myDiv1 {
position: absolute;
width: 200px;
height: 200px;
background-color: aqua;
}
#myDiv2 {
position: absolute;
width: 200px;
height: 200px;
background-color: salmon;
}
#myDiv3 {
position: absolute;
width: 200px;
height: 200px;
background-color: slateblue;
}
</style>
</head>
<body>
<script>
//控制台打印拖放位置
DragDrop.addHandler("dragstart", function (event) {
var status = document.getElementById("status");
console.log("Started dragging " + event.target.id);
});
DragDrop.addHandler("drag", function (event) {
var status = document.getElementById("status");
console.log("<br/> Dragged " + event.target.id + " to (" + event.x +
"," + event.y + ")");
});
DragDrop.addHandler("dragend", function (event) {
var status = document.getElementById("status");
console.log("<br/> Dropped " + event.target.id + " at (" + event.x +
"," + event.y + ")");
});
//加载拖放事件
DragDrop.enable()
</script>
<p id="status"></p>
<div id="myDiv1" class="draggable"></div>
<div id="myDiv2" class="draggable"></div>
<div id="myDiv3" class="draggable"></div>
</body>
</html>