go-site/resources/login/script.js

$(document).ready(function(){
	$('.pass_show').append('<span class="ptxt">Показать</span>');

	$('.ptxt').on('mousedown', function(){
		$(this).prev().attr('type', function(index, attr){return 'text';})
	});

	$('.ptxt').on('mouseup', function(){
		$(this).prev().attr('type', function(index, attr){return 'password';})
	});
});