在火狐中添加innerText属性

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].textContent;
		  else if(childS[i].nodeType==3)
		   anyString += childS[i].nodeValue;
		 }
		 return anyString;
		}
	   );
	   HTMLElement.prototype.__defineSetter__(     "innerText",
		function(sText){
		 this.textContent=sText;
		}
	   );
	}