常用兼容方法

1.总结事件兼容

var EventUtil = {
    addHandler: function (element, type, handler) {//添加监听事件兼容
        if (element.addEventListener) {
            element.addEventListener(type, handler, false);
        } else if (element.attachEvent) {//兼容ie
            element.attachEvent("on" + type, handler);
        } else {
            element["on" + type] = handler;
        }
    },
    getEvent: function (event) {//event兼容
        return event ? event : window.event;
    },
    getTarget: function (event) {//获取当前目标元素
        return event.target || event.srcElement;
    },
    preventDefault: function (event) {//阻止默认事件兼容
        if (event.preventDefault) {
            event.preventDefault();
        } else {//兼容ie
            event.returnValue = false;
        }
    },
    removeHandler: function (element, type, handler) {//移除监听事件兼容
        if (element.removeEventListener) {
            element.removeEventListener(type, handler, false);
        } else if (element.detachEvent) {//兼容ie
            element.detachEvent("on" + type, handler);
        } else {
            element["on" + type] = null;
        }
    },
    stopPropagation: function (event) {//阻止事件冒泡兼容
        if (event.stopPropagation) {
            event.stopPropagation();
        } else {//兼容ie
            event.cancelBubble = true;
        }
    },
    getRelatedTarget: function (event) {//mouseout和mouseover事件时，获取相关元素
        if (event.relatedTarget) {
            return event.relatedTarget;
        } else if (event.toElement) {
            return event.toElement;
        } else if (event.fromElement) {
            return event.fromElement;
        } else {
            return null;
        }
    },
    getButton: function (event) {//mousedown和mouseup事件，返回值 0表示鼠标左键，1表示中间的鼠标按钮（鼠标滚轮按钮），2表示次鼠标右键
        if (document.implementation.hasFeature("MouseEvents", "2.0")) {
            return event.button;
        } else {
            switch (event.button) {
                case 0:
                case 1:
                case 3:
                case 5:
                case 7:
                    return 0;
                case 2:
                case 6:
                    return 2;
                case 4:
                    return 1;
            }
        }
    },
    getWheelDelta: function(event) {//兼容鼠标滚轮事件
      if (event.wheelDelta) {
          //在 Opera 9.5 之前的版本中，wheelDelta 值的正负号是颠倒的。如果你打算支持早期的 Opera 版本，就需要使用浏览器检测技术来确定实际的值
        return (client.engine.opera && client.engine.opera < 9.5 ?
          -event.wheelDelta : event.wheelDelta);
      } else {
        return -event.detail * 40;
      }
    },
    getCharCode: function(event){ //兼容获取当前键盘事件的ASCII编码
         if (typeof event.charCode == "number"){ 
             return event.charCode; 
         } else { 
             return event.keyCode; 
         }
     },
     getClipboardText: function(event){//兼容获取剪贴板内容
        var clipboardData = (event.clipboardData || window.clipboardData);
        return clipboardData.getData("text");
    },
    setClipboardText: function(event, value){//兼容设置剪贴板内容
        if (event.clipboardData){
            return event.clipboardData.setData("text/plain", value);
        } else if (window.clipboardData){//兼容ie
            return window.clipboardData.setData("text", value);
        }
    },
};