JS: How to make document.getElementById cross-browser?

Question

document.getElementById doesn\'t seem to work across all browsers (I mean some old ones) and I am sure there are developers who are not aware of this.

Answer 1

getElemID(obj){

if(document.getElementByID){
 return document.getElementByID(obj);
}

 else if (document.all){
  return document.all[obj];
  }

  else if (document.layers){
     return  document.layers[obj];
     }

  else {
       alert("Could not find support");
       return false;
       }
}