1 
  2 goog.provide('xrx.markup');
  3 
  4 goog.require('goog.dom');
  5 
  6 
  7 xrx.markup = function() {
  8   
  9 };
 10 
 11 
 12 /** @const */ xrx.markup.REF = 'data-xrx-ref';
 13 
 14 
 15 xrx.markup.prototype.element = function(id) {
 16   var element = goog.dom.getElement(this.id);
 17 
 18   if (!element) throw Error('Element with ID <' + id.toString() + '> does not exist.');
 19   
 20   return element;  
 21 };
 22 
 23 
 24 
 25 xrx.markup.prototype.ref = function() {
 26   var ref = this.element().getAttribute(xrx.markup.REF);
 27   
 28   if (ref === '') throw Error('A non empty ref attribute is missing. ' + element.toString());
 29   
 30   return ref;
 31 };
 32 
 33 
 34 
 35 xrx.markup.id = function(element) {
 36   var id = element.getAttribute('id');
 37   
 38   if (id === '') throw Error('A non empty id attribute is missing. ' + element.toString());
 39   
 40   return id;
 41 };