Use Ajax to check form fields and submit

ajax_form_submit.js

var isHttps    = location.protocol.match(/https/);
var http       = isHttps ? 'https://' : 'http://';
var site_url   = http + location.host + '/yoursite';

$(function(){
  $('#form-btn').on('click',function(event){

		var email_test = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
		var form_name    = $('#form-name').val();
		var form_email   = $('#form-email').val();
		var form_contact = $('#form-contact').val();
		var form_message = $('#form-message').val();
		var page 		 = $('#page-category').data("category-value");

		if(form_name == "" || form_email == "" || form_contact == "" || form_message == "") {
			$('#form-notification').html('<div class="alert alert-danger form-msg text-center">Please complete all the fields</div>').hide().fadeIn();
		  	var error = 1;
			$('.form-group').each(function(){
				var field = $(this).find('.form-field');
				
				if(field.val() == ""){ 
					field.addClass('error-field');
				} else {
					field.removeClass('error-field');
				}
			});
		} else if( !email_test.test(form_email) ){
			$('#form-notification').html('<div class="alert alert-danger form-msg text-center">Invalid E-mail Address</div>').hide().fadeIn();
			var error = 1;
		} else if( form_contact.length < 10 ) {
			$('#form-notification').html('<div class="alert alert-danger form-msg text-center">Contact No. must be greater than 10 digits</div>').hide().fadeIn();
			var error = 1;
		}

		if( error == 1 ){
			console.log('error');
		} else {

			var formdata = {
				form_name    : form_name,
				form_email   : form_email,
				form_contact : form_contact,
				form_message : form_message,
				page 	     : page
		  	};

			$.ajax({
				    data     : formdata,
				    type     : 'POST',
				    dataType : 'JSON',
				    url      : site_url + '/ajax-forms.php',
				    success: function(response){
					    $('#cf-notification').html(response.notification).hide().fadeIn();
						if(response.status == 'success') {
							//$('#form-notification').html(response.notification).hide().fadeIn().delay(12000).fadeOut('slow');
							//$('.form-field').val('');
							//$('.form-field').removeClass('error-field');
							window.location.href = "/thank-you/";
			      		}
				      	return false;	
				    },
				    error: function(){
				        console.log('error');
				    }
				});
			$('.form-field').removeClass('error-field');
		}
		event.preventDefault();
	});
});