Rails，AJAX表单验证

Question

I am new to jQuery, AJAX, and javascript in general, and I am trying to do some front end validation for a rails form that uses an ajax call to have the server run a query. It seems to work well, if I am in the debugger (since the AJAX call has enough time to return and stop the submission of the form), but it wont work all of the time when I am just testing it without the debugger. I believe this happens because after the ajax call, the javascript validation method exits, and the form submits. Here is my javascript method

  $('#runner-job-submit').click(function(e) {
    runnerJobValidation(e);
  });

  function runnerJobValidation(e) {
    var user_login = $('#user_login').val();
    var name = $('#name').val();
    var location = $('#location').val();
    var description = $('#description').val();
    var user_exists;
    //AJAX call to check if user exists in the database
    $.post("/jobs/user_exists", {user_login: user_login}, function (response) {
      if(response == "false") {
        $('#runner-new-job-errors').html('');
        e.preventDefault();
        $('#runner-new-job-errors').append('<small style="color:red"> User doesnt exist </small>');
      }
    });
    if(user_login == "" || name == "" || location == "" || description == "") {
        $('#runner-new-job-errors').html('');
        e.preventDefault();
        $('#runner-new-job-errors').append('<small style="color:red"> Please fill out all fields </small>');
      }

  }

And here is my controller action url it is hitting

      def user_exists?
        user_login = params[:user_login]
        user = User.where("login = ?", user_login).first
        user_exists = user.present?
        respond_to do |format|
          format.js  { render :json => user_exists.to_json}
          format.html { redirect_to jobs_path }
        end
  end

Can someone please tell me the correct way to do this. I feel the solution is to somehow prevent runnerJobValidation() from exiting before response is received from the server, but I just dont know how to do this.

Answer 1

You are trying to make an synchronous ajax request. In short, you can do it by set async in ajax object to false.

You can found your solution here : How to make JQuery-AJAX request synchronous .

Hope this help.

Answer 2

You can user jQuery validation plugin like http://jqueryvalidation.org/

For validation you should add new validation method http://jqueryvalidation.org/jQuery.validator.addMethod/

Something like this:

jQuery.validator.addMethod("user_exists", function(value, element, param) {
    var isSuccess = false;
    isSuccess = $.ajax(type: "POST", url: "/jobs/user_exists", data: {user_login: user_login}, dataType: "json").responseText == "false" ? false : true;
    return isSuccess;
}, jQuery.format("User already exists!"));

And for form submit:

 $("#myform").validate({
  submitHandler: function(form) {
    // some other code
    // maybe disabling submit button
    // then:
    $(form).submit();
  }
 });

About how to properly use plugin read docs at http://validation.bassistance.de/documentation/