Workaround to prevent under-layer scrolling on iOS

layout.js

var myScrollTop = 0;

jQuery.fn.openLightbox = function() {

	if (/iPhone|iPad|iPod/i.test(navigator.userAgent)) {
		myScrollTop = $('body').scrollTop();

		var wpadminbar = 0; 
		if ($('#wpadminbar').length != 0) {
			wpadminbar = $('#wpadminbar').outerHeight();
		}

		thisOffset = myScrollTop - wpadminbar;
		offsetString = "-" + thisOffset + "px";

		$('.content-area').css({
		    'top': offsetString,
		    'position':'fixed'
		});

	}

}

jQuery.fn.closeLightbox = function() {

	if (/iPhone|iPad|iPod/i.test(navigator.userAgent)) {

		$('.content-area').css({
		    'top': "auto",
		    'position':'static'
		});

		$( "body" ).scrollTop( myScrollTop );
		myScrollTop = 0;

	}

}