// define prototype for different user-agent
function isIE(){ //ie?
  if (window.navigator.userAgent.indexOf("MSIE")>=1) return true;
  else return false;
}

if(!isIE()) {
// define "innerText" function for non-ie browser
// @see http://www.firefox.net.cn/newforum/viewtopic.php?p=29911#29911 for detail
HTMLElement.prototype.__defineGetter__("innerText", 
function () {
  var it = "";
  var childS = this.childNodes;
  for(var i=0; i<childS.length; i++) {
    if(childS[i].nodeType==1) it += childS[i].tagName=="BR" ? '\n' : childS[i].innerText;
    else if(childS[i].nodeType==3) it += childS[i].nodeValue;
  }
  return it;
});
}