/**
   *
   * Copyright (c) 2008 Tom Deater (http://www.tomdeater.com)
   * Licensed under the MIT License:
   * http://www.opensource.org/licenses/mit-license.php
   *
   * uses an iframe, sized in ems, to detect font size changes then trigger a "fontresize" event
   * heavily based on code by Hedger Wang: http://www.hedgerwow.com/360/dhtml/js-onfontresize.html
   *
   * "fontresize" event is triggered on the document object
   * subscribe to event using: $(document).bind("fontresize", function (event, data) {});
   * "data" contains the current size of 1 em unit (in pixels)
   * 
   */
   
  jQuery.onFontResize = (function ($) {
  	// initialize
  	$(document).ready(function () {
  		var $resizeframe = $("<iframe />")
  			.attr("id", "frame-onFontResize" + Date.parse(new Date))
  			.css({width: "100em", height: "10px", position: "absolute", borderWidth: 0, top: "-5000px", left: "-5000px"})
  			.appendTo("body");
  			
  		if ($.browser.msie) {
  			// use IE's native iframe resize event
  			$resizeframe.bind("resize", function () {
  				$.onFontResize.trigger($resizeframe[0].offsetWidth / 100);
  			});
  		} else {
  			// everyone else uses script inside the iframe to detect resize
  			var doc = $resizeframe[0].contentWindow || $resizeframe[0].contentDocument || $resizeframe[0].document;
  			doc = doc.document || doc; 
  			doc.open();
  			doc.write('<div id="em" style="width:100em;height:10px;"></div>');
  			doc.write('<scri' + 'pt>window.onload = function(){var em = document.getElementById("em");window.onresize = function(){if(parent.jQuery.onFontResize){parent.jQuery.onFontResize.trigger(em.offsetWidth / 100);}}};</scri' + 'pt>');
  			doc.close();
  		}
  	});
  	
  	return {
  		// public method, so it can be called from within the iframe
  		trigger: function (em) {
  			$(document).trigger("fontresize", [em]);
  		}
  	};
  }) (jQuery);