定义属于自己的事件库

闲来无事，写一个自己的事件库，这样以后每次在用的时候也会方便很多。
小二，上代码：

/**
 * Created by iwen on 16/6/15.
 */
var iwenEvent = {};
iwenEvent.event = {};
//添加事件
iwenEvent.event.on = function(id, type, handler){
    var dom = iwenEvent.dom.getId(id);
    if(dom.addEventListener){
        dom.addEventListener(type, handler, false);
    }else if(dom.attachEvent){
        dom.attachEvent('on' + type, handler);
    }else{
        dom['on' + type] = handler;
    }
};
//解除事件
iwenEvent.event.off = function(id, type, handler){
    var dom = iwenEvent.dom.getId(id);
    if(dom.removeEventListener){
        dom.removeEventListener(type, handler);
    }else if(dom.detachEvent){
        dom.detachEvent(type, handler);
    }else{
        dom['on' + type] = null;
    }
}
// 获取事件对象
iwenEvent.event.getEvent = function(event){
    return event ? event : window.event;
}
//获取元素对象
iwenEvent.event.getTarget = function(event){
    var event = iwenEvent.event.getEvent(event);
    return event.target;
}
iwenEvent.dom = {};
iwenEvent.dom.getId = function(id){
    return document.getElementById(id);
};
iwenEvent.dom.getTagName = function(names){
    if(document.getElementsByClassName){
        return document.getElementsByClassName(names);
    }
    return "不支持getElementsByClassName";
}
iwenEvent.dom.getClassName = function(names){
    if(document.getElementsByClassName){
        return document.getElementsByClassName(names);
    }
    return "不支持getElementsByClassName";
}
iwenEvent.dom.css = function(id, key, value){
    iwenEvent.dom.getId(id).style[key] = value;
}
iwenEvent.dom.html = function(id, value){
    if(value){
        iwenEvent.dom.getId(id).innerHTML = value;
    }else{
        return iwenEvent.dom.getId(id).innerHTML;
    }
}