SweetAlert with Java Servlet

Question

I wanted to pause form's onsubmit, so I could ask user to confirm action before proceed. So here's my form:

            <form action="<%= request.getContextPath()%>/Controller" 
                  method="POST" id="remove_book" 
                  onsubmit="alertBookInfo('return_book')">
            </form>

Then, I created the JavaScript function, using SweetAlert:

function alertInfo(action) {
document.querySelector(action).addEventListener('submit', function (e) {
    var form = this;
    e.preventDefault();
    if (action === "remove_book") {
        swal({
            title: "Remove book?",
            text: "Watch out",
            type: "warning",
            showCancelButton: true,
            confirmButtonColor: "#DD6B55",
            confirmButtonText: "Yes.",
            cancelButtonText: "No.",
            closeOnConfirm: false,
            closeOnCancel: false
        },
        function (isConfirm) {
            if (isConfirm) {
                swal({
                    title: "Deleted.",
                    text: "Done.",
                    type: "success"
                }, function () {
                            form.submit();
                });
            } else {
                swal("Cancelled", "Not done.", "error");
            }
        });
    }
});
}

But for some reason, I am unable to prevent page reload on form submit. Am I doing someting wrong?

PS: I already tried with return alertInfo() in form and returning boolean value from JS function with no success.

Answer 1

If you don't want the page reloads you could use an AJAX call. When you use the submit() you will always reload the page because is how submit works.

$.ajax({
        method: "POST",
        url: YOUR_ACTION_URL,
        data: $('form').serialize(),
        success: function(data){
            //here you could add swal to give feedback to the user
        }
    });

In your controller you have to define the method as produces JSON, if you are using Spring, the annotation is @ResponseBody

Answer 2

Why not call the function from the form like this, the the alert will be prompt before submitting the form:

HTML

<form action="<%= request.getContextPath()%>/Controller" method="GET" id="remove_book" onclick="myAlertFunction(event)">
  <input type="submit">
</form>

JavaScript

function myAlertFunction(event) {
  event.preventDefault()
  swal({
      title: "Remove book?",
      text: "Watch out",
      type: "warning",
      showCancelButton: true,
      confirmButtonColor: "#DD6B55",
      confirmButtonText: "Yes.",
      cancelButtonText: "No.",
      closeOnConfirm: false,
      closeOnCancel: false
    },
    function(isConfirm) {
      if (isConfirm) {
        swal({
          title: "Deleted.",
          text: "Done.",
          type: "success"
        }, function() {
          $("#remove_book").submit();
        });
      } else {
        swal("Cancelled", "Not done.", "error");
      }
    });
}

And if you want to prevent the reload, you can always use event.preventDefault()

Here is an example: JSFiddel