Скрипт проверки формы , перед отправкой

		$('.send').on('click',function(e){ 
			e.preventDefault(); 
			var $inputArr = $('.c-ordering-form input'); 
			var inputLength = $inputArr.length; 
			var count = 0; 
			$.each($inputArr,function(i,v){ 
				if ($(v).val() == ''){ 
					$('.error-text, .c-ordering-form').addClass('error'); 
					$(v).addClass('error'); 
				} else { 
					count += 1 
					$(v).removeClass('error'); 
					count == inputLength ? $('.c-ordering-form , .error-text').removeClass('error') : ''			 
				} 
			}) 
		})

.main-input { 
		display: block; 
		margin-bottom: 5px; 
	} 
	.main-input.error { 
		border-color: red; 
	} 
 
	.error-text { 
		opacity: 0; 
		visibility: hidden; 
	} 
	.error { 
		opacity: 1; 
		visibility: visible; 
	}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
<form class="c-ordering-form"> 
  <input class="main-input required" type="text" placeholder="ФИО" required="required" /> 
  <input class="main-input required" type="email" placeholder="E-mail" required="required" /> 
  <input class="main-input required" type="tel" placeholder="Телефон" required="required" /> 
  <button class="send">отправить</button> 
  <div class="error-text">Ошибка</div> 
</form>