跨浏览器实现兼容事件绑定/移除

function AddEvent(element,type,fn,fg)
{
    if(element.addEventListener)
        element.addEventListener(type,fn,fg);
    else
        element.attachEvent('on'+type,fn,false);
}
function RemoveEvent(element,type,fn,fg)
{
    if(element.removeEventListener)
        element.removeEventListener(type,fn,fg);
    else
        element.detachEvent('on'+type,fn,false);
}