iOS: Fixed position elements on input focus

iOS: Fixed position elements on input focus

$(document).ready(function() {
	$("input, select, textarea").on('focus', function() {
		$("#header").css({
			'position': 'absolute',
			'top': $(document).scrollTop()
		});
		focusing = true;
	})
	$("input, select, textarea").on('blur', function() {
		$("#header").css({
			'position': 'fixed',
			'top': 0
		});
		focusing = false;
	})
});

$(window).scroll(function() {
	if ( focusing ) $("#header").css({ 'top': $(document).scrollTop() });
});