FireFox支持innerText的方法

function isIE(){ //ie? 
if (window.navigator.userAgent.toLowerCase().indexOf("msie")>=1) 
    return true; 
else 
    return false; 
} 

if(!isIE()){ //firefox innerText define
    HTMLElement.prototype.__defineGetter__("innerText", 
    function(){
        var anyString = "";
        var childS = this.childNodes;
        for(var i=0; i<childS.length; i++) { 
            if(childS[i].nodeType==1)
                //anyString += childS[i].tagName=="BR" ? "\n" : childS[i].innerText;
                anyString += childS[i].innerText;
            else if(childS[i].nodeType==3)
                anyString += childS[i].nodeValue;
        }
        return anyString;
    } 
    ); 
    HTMLElement.prototype.__defineSetter__("innerText", 
    function(sText){
        this.textContent=sText; 
    } 
    ); 
}