This function does exactly what it says on the tin: it gets the document object of a frame or iframe.

The code

This function relies on code explained elsewhere:

• HOWTO determine the browser name and version number

/**
 * Cross browser function for getting the document element of a frame or iframe.
 * @param {HTMLIFrameElement|HTMLFrameElement} frame Frame element
 * @return {HTMLDocument}
 */
goog.dom.getFrameContentDocument = function(frame) {
  return goog.userAgent.SAFARI ?
          (frame.document || frame.contentWindow.document) :
          (frame.contentDocument || frame.contentWindow.document);
};

The code walkthrough

This function is so short that it doesn't really need a walkthrough. The only thing to know is that Safari needs to be special-cased because it doesn't support the contentDocument property on a frame. Luckily it does support a proprietary frame.document property which accomplishes the same thing.

Further reading

• HOWTO determine the browser name and version number