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

function getDOM() {
    if (document.getElementById) {
        return document.getElementById; 
    }

    var window_document = window.document || {};
    var elements = window_document.all || window_document.layers;
    if(elements) {
        return function(x) { return elements[x]; }
    }

    // everything failed
    throw new InternalError('No means to "getElementById"');
}

... then

var getElementById;
try {
    getElementById = getDOM();
} catch(err) {
    alert(err);
}
// implicit 0K
var oHTMLElement = getElementById('#main');

Answer 2

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;
       }
}

Answer 3

If document.getElementById doesn't work then either:

• You're doing it wrong (invalid HTML, trying to access names instead of IDs, etc)

or

• You're working with Netscape 4.x and Internet Explorer 4.x

There are three ways to deal with browsers of this era.

• Tell people to upgrade. They are unmaintained, security hole ridden nightmares for user and author alike.
• Build on stuff that works and make sure your JS checks for the existence of getElementById and friends before trying to use them ( if (!document.getElementById) { return false; /* Insufficient DOM to bother with JS here */ } )
• Learn about document.all and document.layers

Answer 4

Are you sure its not this kind of problem? Have a look its interesting, I didn't know that before.

However, to complement what is already suggested by David Dorward, you write a function like below.

function getElement (id) {

  if (document.getElementById) {
    return document.getElementById(id);
  }

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

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