js跨浏览器阻止事件冒泡的代码

function stopPropagation(e) {  
    e = e || window.event;  
    if(e.stopPropagation) { //W3C阻止冒泡方法  
        e.stopPropagation();  
    } else {  
        e.cancelBubble = true; //IE阻止冒泡方法  
    }  
}