取消冒泡
function canclebubble(event){
var event = event||window.event; //兼容火狐
if(event.stopPropagation){
event.stopPropagation(); //标准浏览器
}else{
event.cancaleBubble==true; //ie
}
阻止默认行为
function stopevent(event){
var event = event||window.event; //兼容火狐
if(event.preventDefault){
event.preventDefault(); //标准浏览器
}else{
event.returnValue==false; //ie
}