gistfile1.js

// Original code
$('.__select-email .textfield')
	.removeClass('__required __invalid')
	.addClass('__' + error.type)
	.find('input[name="email"]')
	.after('<label class="error">' + error.text + '</label>');
	
	
// Short method	
var input = $('.__select-email .textfield')
		.removeClass('__required __invalid')
		.addClass('__' + error.type)
		.find('input[name="email"]'),

$('<label class="error">' + error.text + '</label>')
	.insertAfter(input)
	.width(input.width());
	
	
// Another method
$.fn.setElWidthAndInsertAfter = function(el) {
	return $(el)
		.width(this.width())
		.insertAfter(this);
}

$('.__select-email .textfield')
	.removeClass('__required __invalid')
	.addClass('__' + error.type)
	.find('input[name="email"]')
	.setElWidthAndInsertAfter('<label class="error">' + error.text + '</label>');