Submit button and form not working when attempting

Question

I know there are numerous questions and answers on how to prevent page reload after form submit with AJAX but I just couldn't get mine to work. I've tried setting the button to type: button which just disables the button completely. When I try onsubmit: return false on the form, this results in nothing clicking the button. Using jQuery to prevent default also didn't work out. What I want is to send this email with PHP retrieving data from the form without the page from reloading. Any help would be highly appreciated.

Form

<?php include('php/interuni_process.php');?>                 
  <form class="form_pro" action="index.php" method="post" role="form">

    <input type="text" class="form" name="E-mail" placeholder="E-mail" value="<?= $email ?>">
    <div class="error"><?= $email_error ?></div>
    <button name="submit" type="submit" class="action_button"></button>
 </form>

PHP

    $email_error = "";
    $email = "";


if ($_SERVER["REQUEST_METHOD"] == "POST") {


  if (empty($_POST["E-mail"])) {
    $email_error = "E-mail is required";
  } else {
    $email = test_input($_POST["E-mail"]);

    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
      $email_error = "Invalid email format"; 
    }
  }

  if ($email_error == '' ){
      unset($_POST['submit']);

      $to = " Whoever <$email>";
      $subject = 'Hello';
      $message = "Hello, $firstname!";

      if (mail($to, $subject, $message, $headers)){
       $email = '';
      }
  }

}

function test_input($data) {
  $data = trim($data);
  $data = stripslashes($data);
  $data = htmlspecialchars($data);
  return $data;
}

I've also tried

$( document ).ready(function() {
    $(".form_pro").submit(function(e) {
        e.preventDefault();

        $.ajax({
            type: "POST",
            url: "php/interuni_process.php",
            data: $(this).serialize(), 
            success: function(data) {

            },
            error: function() {

            }
        });
    });
});

Answer 1

i think you have to change the logic flow to do so. try the following code which i have tested on my PC.

<script src="jquery-1.11.1.js"></script>
<form id="myData" class="form_pro" method="post" role="form">

    <input type="text" class="form" name="E-mail" placeholder="E-mail" value="">
    <div class="error"></div>
    <button name="submit" type="button" class="action_button" onclick="doSubmit();">OK</button>
 </form>

<script>
    function doSubmit(){
        $.ajax({
            url:'interuni_process.php',
            data:$("#myData").serialize(),
            type:'POST',
            success: function (data, textStatus, jqXHR) {
                if(data==="SUCCESS"){
                    $(".error").text("No error occurred");
                }else{
                    $(".error").text("Error occurred: "+ data);
                }
            }
        });
    };
</script>

and sample code for "interuni_process.php" is

<?php
    $eMail=$_POST["E-mail"];

    if($eMail===""){ //or whatever process condition you want to do
        echo "Email cannot be blank";
    }else{
        echo "SUCCESS";
    }
?>

modify business logic as your per requirement

Answer 2

Firstly You remove action from HTML <form> Tag

 <form class="form_pro" method="post" role="form">

after change add return false to your jquery function as per below

$(document).on('submit','.form_pro',function(){
    $.ajax({
        url:'interuni_process.php',
        type:'POST'
    });
    return false;
});