$(document).ready(function() {
   //Activate FancyBox
   $("a.iframe").fancybox({
      // avoid closing fancybox with clickable content
      'hideOnContentClick': false,
      // set the fancybox size
'padding': '0', //optional
'width': '75%', // or whatever size
'height': '75%',
'type': 'iframe' 
      });
   });