Dynamic resizing of iframe in a different domain

iframe.js

$(function(){
	var parent_url;
	
	// Create the hidden input field that will hold the parent_url variable.
	$("form").append('<input name="parent_url" id="parent_url" />');
	
	// We check to see if location hash is empty. It should only go in here if you're using IE and after the form as been submitted.
	if(document.location.hash == ""){
		var search 		= document.location.search,
				id 				= "parent_url=",
				hs_start	= search.indexOf('parent_url'),
				hs_end 		= search.indexOf('&product_service');

		// Get the parent URL from the URL parameters sent by the form
		parent_url = decodeURIComponent( search.substr(hs_start + id.length, hs_end - id.length - 1) );
	}
	// If location hash is not empty, then we just assign it to the variable parent_url
	else{
		parent_url = decodeURIComponent( document.location.hash.replace( /^#/, '' ) );
	}
	// We assign the value of the parent_url to the hidden input element. That way if document.location.hash is not accessible, it can be accessed 
	$("#parent_url").val(parent_url);
	
	// This is the function that posts a message to the parent for it to resize the iframe
	function setHeight() {
		$.postMessage({ if_height: $('body').outerHeight( true ) }, parent_url, parent );
	};
	setHeight();
	
	// Update all the links to attach the parent url to the href attribute
	$("a").each(function() {
		$(this).attr("href", $(this).attr("href")+"#"+parent_url);
	});
});

parent.js

$.receiveMessage(function(e){
	var h = Number(e.data.replace( /.*if_height=(\d+)(?:&|$)/, '$1'));
	if(!isNaN(h) && h > 0 && h !== if_height){
		$("#iframe_id").height(if_height = h);
	}
});