I have tested version V2 for Fancybox.

How to set (automatic) resized function with content inside V2?

.fancybox({
'width' : '98%',
'height' : '98%',
type: 'iframe',
autoSize : false,
beforeLoad : function() {
this.width = parseInt(this.href.match(/width=[0-9]+/i)[0].replace('width=',''));
this.height = parseInt(this.href.match(/height=[0-9]+/i)[0].replace('height=',''));
}
});