lib/Ext/core/Ext-more.js
function(el) {
        if (!el || !document) {
            return null;
        }

        return el.dom ? el.dom : (typeof el == 'string' ? document.getElementById(el) : el);
    }
function(el) {
        if (!el || !document) {
            return null;
        }

        return el.dom ? el.dom : (typeof el == 'string' ? document.getElementById(el) : el);
    }
Return the dom node for the passed String (id), dom node, or Ext.Element.
Here are some examples:

// gets dom node based on id
var elDom = Ext.getDom('elId');

// gets dom node based on the dom node
var elDom1 = Ext.getDom(elDom);

// If we don't know if we are working with an
// Ext.Element or a dom node use Ext.getDom
function(el){
var dom = Ext.getDom(el);
// do something with the dom node
}

__Note:__ the dom node to be found actually needs to exist (be rendered, etc)
when this method is called to be successful.
@param {Mixed} el
@return {HTMLElement}