form

  form(name="input" action="/submit/form" method="POST" class="sendForm")
    <!-- - Hidden input send form-->
    input(type="hidden" name="project_name" value="Название сайта")
    input(type="hidden" name="admin_email" value="ТУТ ДОЛЖЕН БЫТЬ ВАША ПОЧТА НА КОТОРЫЕ БУДУТ ПРИХОДИТЬ ЗАЯВКИ!!")
    input(type="hidden" name="form_subject" value="Заявка на лендинг")
    <!-- - End Hidden input send form-->
    input(type="text" name="Name" placeholder="Ваше имя" class="inp")
    input(type="email" name="Email" placeholder="Ваша Email" class="inp")
    input(type="tel" name="telephone" placeholder="Ваш телефон" class="inp inp__phone")
    textarea(rows="5" cols="45" name="message" placeholder="Ваше сообщения" class="inp inp__area")
    input(type="reset" value="Очистить" class="btn__clear")
    input(type="submit" value="Отправить" class="btn__send")

mail.js + validation

  var saleMe = (function () {

  var init = function () {
      _setUpListners();
      // то, что должно произойти сразу
      };
  var _setUpListners = function () {
  $('.sendForm').on('submit', _submitForm);
      };

  var _submitForm = function (ev) {
    ev.preventDefault();

    var form = $(this),
        url = 'mail.php',
        defObj = _ajaxForm(form, url);
  };

  var _ajaxForm = function (form, url) {
    var popup = $('.popup');
    if (!validation.validateForm(form)){
      return false;
    } else {
      $.ajax({
        type: "POST",
        url: url, //Change
        data: form.serialize()
      }).done(function() {
        $('.popup').css('background-color', '#7ee689');
        setTimeout(function() {
          // Done Functions
          popup.css('background-color', '#fff');
          form.trigger("reset");
        }, 1000);
      });
      return true;
    }
  };
  return {
    init: init
  };
  })();

  saleMe.init();



var validation = (function () {

  var init = function () {
	    _setUpListners();
	    // то, что должно произойти сразу
  	  };

  var _setUpListners = function () {
  	//чистим поля от ошибок
  	 $('form').on('keydown', '.has-error', _removeError);
    $('form').on('reset', _clearForm);
    };

  var _removeError = function () {

  	$(this).removeClass('has-error');
  	$(this).find('.inp').removeClass('has-error');

  };
  var _clearForm = function (form) {
  	var form = $(this);
  	form.find('input, textarea').trigger('hideTooltip');
  	form.find('.has-error').removeClass('has-error');
  };

 var validateForm = function (form) {

 	var elements = form.find('input, textarea').not('input[type="file"], input[type="hidden"]'),
 	    valid = true;
 	    //пройдемся по всем эелемантам формы
 	 $.each(elements, function (index, val) {
 	 	var element = $(val),
 	 	    val = element.val(),
 	 	    pos = element.attr('qtip-position');

 	 	if (val.length === 0) {
 	 		//красный фон
 	 	  element.addClass('has-error');
     // _createQtip(element, pos);
 	 	 valid = false;
 	 	}

 	 });

 	 return valid;
 };

  return {
	  init: init,
	  validateForm: validateForm

  };

})();

validation.init();

mail.php

<?php
$method = $_SERVER['REQUEST_METHOD'];
//Script Foreach
$c = true;
if ( $method === 'POST' ) {
	$project_name = trim($_POST["project_name"]);
	$admin_email  = trim($_POST["admin_email"]);
	$form_subject = trim($_POST["form_subject"]);
	foreach ( $_POST as $key => $value ) {
		if ( $value != "" && $key != "project_name" && $key != "admin_email" && $key != "form_subject" ) {
			$message .= "
			" . ( ($c = !$c) ? '<tr>':'<tr style="background-color: #f8f8f8;">' ) . "
			<td style='padding: 10px; border: #e9e9e9 1px solid;'><b>$key</b></td>
			<td style='padding: 10px; border: #e9e9e9 1px solid;'>$value</td>
		</tr>
		";
	}
}
} else if ( $method === 'GET' ) {
	$project_name = trim($_GET["project_name"]);
	$admin_email  = trim($_GET["admin_email"]);
	$form_subject = trim($_GET["form_subject"]);
	foreach ( $_GET as $key => $value ) {
		if ( $value != "" && $key != "project_name" && $key != "admin_email" && $key != "form_subject" ) {
			$message .= "
			" . ( ($c = !$c) ? '<tr>':'<tr style="background-color: #f8f8f8;">' ) . "
			<td style='padding: 10px; border: #e9e9e9 1px solid;'><b>$key</b></td>
			<td style='padding: 10px; border: #e9e9e9 1px solid;'>$value</td>
		</tr>
		";
	}
}
}
$message = "<table style='width: 100%;'>$message</table>";
function adopt($text) {
	return '=?UTF-8?B?'.base64_encode($text).'?=';
}
$headers = "MIME-Version: 1.0" . PHP_EOL .
"Content-Type: text/html; charset=utf-8" . PHP_EOL .
'From: '.adopt($project_name).' <'.$admin_email.'>' . PHP_EOL .
'Reply-To: '.$admin_email.'' . PHP_EOL;
mail($admin_email, adopt($form_subject), $message, $headers );