function getevent(){ //获取浏览器事件，同时兼容ie和ff的写法 
if(document.all) return window.event; 
func=getevent.caller; 
while(func!=null){ 
var arg0=func.arguments[0]; 
if(arg0){ 
if((arg0.constructor==event 　　 arg0.constructor ==mouseevent) 
　　 (typeof(arg0)=="object" && arg0.preventdefault && arg0.stoppropagation)){ 
return arg0; 
} 
} 
func=func.caller; 
} 
return null; 
}

event.returnvalue=false;// for ie 

evt.preventdefault();//for firefox

var source=event.srcelement //ie 

var source=event.target //firefox

function addevent(oelement,sevent,func){ 
if (oelement.attachevent){ 
oelement.attachevent(sevent,func); 
} 
else{ 
sevent=sevent.substring(2,sevent.length); 
oelement.addeventlistener(sevent,func,false); 
} 
}

//注册firefox innertext 
htmlelement.prototype.__definegetter__("innertext", 
function(){ 
var anystring = ""; 
var childs = this.childnodes; 
for(var i=0; i if(childs[i].nodetype==1) 
anystring += childs[i].tagname=="br" ? '\n' : childs[i].innertext; 
else if(childs[i].nodetype==3) 
anystring += childs[i].nodevalue; 
} 
return anystring; 
} 
); 
htmlelement.prototype.__definesetter__("innertext", 
function(stext){ 
this.textcontent=stext; 
} 
);