static/ext/src/dom/AbstractElement_static.js
function() {
            return Math.max(!Ext.isStrict ? document.body.scrollHeight : document.documentElement.scrollHeight, this.getViewportHeight());
        }
function() {
            return Math.max(!Ext.isStrict ? document.body.scrollHeight : document.documentElement.scrollHeight, this.getViewportHeight());
        }
Retrieves the document height
@static
@return {Number} documentHeight