Jquery Force Input to Be Filled Before Continue on Load

A great way to improve the user experience of your website is to validate and submit forms without a page refresh.

In this tutorial, I'll show you how easy it is to do just that—validate and submit a contact form without page refresh using jQuery! Let's get started.

What We're Building

In this example, we have a simple contact form with name, email, and phone number. The form submits all the fields to a PHP script without any page refresh, using native jQuery functions.

1. Build the HTML Form

Let's take a look at our HTML markup. We begin with our basic HTML form:

          <div id="contact_form">   <form name="contact" action="">     <fieldset>       <div class="input-box">       <label for="name" id="name_label">Name</label>       <input type="text" name="name" id="name" minlength="3" placeholder="Monty" class="text-input" required/>       </div>              <div class="input-box">       <label for="email" id="email_label">Email</label>       <input type="email" name="email" id="email" placeholder="example@tutsplus.com" class="text-input"/>       </div>              <div class="input-box">       <label for="phone" id="phone_label">Phone</label>       <input type="tel" name="phone" id="phone" class="text-input" placeholder="856-261-9988"/>       </div>              <input type="submit" name="submit" class="button" id="submit_btn" value="Send" />     </fieldset>   </form>     <div class="greetings">     <h1>Contact US</h1>       <p>We are waiting to hear from you!</p>     </div>   </div>

You might notice that I have included adiv with idcontact_form that wraps around the entire form.

Be sure to not miss thatdiv in your own form as we will be needing this wrapperdiv later on. You might also notice that I have left both the action and the method parts of the form tag blank. We actually don't need either of these here, because jQuery takes care of it all later on.

Another important thing is to be sure to include theid values for each input field. Theid values are what your jQuery script will be looking for to process the form with.

We are also doing some very basic client-side validation using HTML5 attributes likerequired andminlength. Theminlength attribute will make sure that users supply a name that is at least three characters long. Similarly, therequired attribute makes sure that users fill out all the form values you need.

You can read more about these attributes in our tutorial on validating form inputs using only HTML5 and Regex.

I've added some CSS styles to produce the following form:

* {   box-sizing: border-box; }  body {   font-family: 'Roboto Slab';   font-size: 1.5rem;   font-weight: 300; }  div#contact_form {   width: 800px;   display: flex;   align-items: stretch;   justify-content: space-evenly;   border: 2px solid black;   padding: 10px; }  div.input-box {   display: flex;   margin: 10px 0;   flex-wrap: wrap; }  div.input-box label {   display: inline-block;   margin: 10px 10px 10px 0;   width: 20%; }  div.input-box input {   font-size: 1.5rem;   border: 1px solid #ccc;   padding: 4px 8px;   flex: 1; }  input.button {   font-size: 1.5rem;   background: black;   color: white;   border: 1px solid black;   margin: 10px;   padding: 4px 40px; }  h1 {   font-size: 5rem;   text-transform: uppercase;   font-family: 'Passion One';   font-weight: 400;   letter-spacing: 2px;   line-height: 0.8; }  div.greetings {   text-align: center;   font-size: 1.2rem;   background-color: #d3d3d3;   background-image: linear-gradient(15deg, transparent 28%, rgba(255, 255, 255, 0.5) 28%);   background-size: 50px; }  div.input-box input.error {     border: 2px dashed red;     background: #fee; }  div.input-box label.error {     color: red;     font-size: 1rem;     text-align: right;     width: 100%;     margin: 10px 0; }

2. Begin Adding jQuery

The next step in the process is to add some jQuery code. I'm going to assume that you have downloaded jQuery, uploaded to your server, and are referencing it in your webpage.

Next, open up another new JavaScript file, reference it in your HTML as you would any normal JavaScript file, and add the following:

          $(function() {      // set up form validation here   });

This function runs as soon as the HTML document is ready. If you have done any work in jQuery previously, this function is the same as jQuery's document.ready function. Inside, we will set up our validation code.

3. Write Some Form Validation

We will now write some basic form validation using jQuery. This will improve upon the validation we have so far. Using a validation library gives us more control over the error messages that are shown to users. It also requires minimal or no changes in the markup of the form.

Starting by loading the jQuery Validation library on your webpage. Now, just add the following code:

$(function () {   $("form").validate(); });

Make sure you pass the right selector when calling thevalidate() method. This will validate the form without requiring you to write any error messages in the HTML or the logic to display and hide different error messages in JavaScript. Try submitting the form without filling in any values or by knowingly adding incorrect input. The form will display a nice error message like the following image.

Using the validation library also allows you to add conditional validation logic to your forms. For example, you will be able to add code that requires a phone number only when the email address has not been provided. I have covered this in more detail in the jQuery form validation tutorial.

4. Process Form Submission With the jQuery AJAX Function

Now we get to the heart of the tutorial—submitting our form without page refresh, which sends the form values to a PHP script in the background. Let's take a look at all the code first, and then I will break it down into more detail next. Add the following code just below the validation snippet we added previously:

$( "form" ).on( "submit", function(e) {      var dataString = $(this).serialize();          // alert(dataString); return false;      $.ajax({       type: "POST",       url: "bin/process.php",       data: dataString,       success: function () {         $("#contact_form").html("<div id='message'></div>");         $("#message")           .html("<h2>Contact Form Submitted!</h2>")           .append("<p>We will be in touch soon.</p>")           .hide()           .fadeIn(1500, function () {             $("#message").append(               "<img id='checkmark' src='images/check.png' />"             );           });       }     });      e.preventDefault();   }); });

There's a lot going on here! Let's break it all down—it's so simple and so easy to use once you understand the process.

We first create a string of values, which are all the form values that we want to pass along to the script that sends the email. This can be achieved pretty easily using the built-inserialize() method in jQuery. This way you don't have to worry about getting and concatenating the values of different valid user inputs yourself.

I've commented out an alert that I sometimes use to be sure I am grabbing the right values, which you may find helpful in the process. If you uncomment that alert and test your form, assuming everything has gone right so far, you should get a message similar to the following:

Now we get to our main AJAX function, the star of today's show. This is where all the action happens, so pay close attention!

$("form").on("submit", function (e) {     var dataString = $(this).serialize();          $.ajax({       type: "POST",       url: "bin/process.php",       data: dataString,       success: function () {         // Display message back to the user here       }     });      e.preventDefault(); });

Basically, what's going on in the code is this: The.ajax() function processes the values from our string calleddataString with a PHP script calledbin/process. php, using the HTTP POST method type. If our script processed successfully, we can then display a message back to the user, and finallyreturn false so the page does not reload. That's it! The entire process is handled right there in these few lines!

There are more advanced things you can do here, other than giving a success message. For example, you could send your values to a database, process them, and then display the results back to the user. So if you posted a poll to users, you could process their vote, and then return the voting results, all without any page refresh required.

Let's summarize what happened in our example, to be sure we have covered everything. We grabbed our form values with jQuery using theserialize() method, and then placed those into a string like this:

var dataString = $(this).serialize();

Then we used jQuery'sajax() function to process the values in thedataString. After that process finishes successfully, we display a message back to the user andreturn false so that our page does not refresh:

          $.ajax({       type: "POST",       url: "bin/process.php",       data: dataString,       success: function() {         $('#contact_form').html("<div id='message'></div>");         $('#message').html("<h2>Contact Form Submitted!</h2>")         .append("<p>We will be in touch soon.</p>")         .hide()         .fadeIn(1500, function() {           $('#message').append("<img id='checkmark' src='images/check.png' />");         });       }     });     return false;

The success part of the script has been filled in with some specific content that can be displayed back to the user. But as far as our AJAX functionality goes, that's all there is to it. For more options and settings, be sure to check out jQuery's documentation on theajax function. The example here is one of the simpler implementations, but even so, it is very powerful, as you can see.

5. Display a Message Back to the User

Let's briefly look at the part of the code that displays our message back to the user, to finish out the tutorial.

First, we change the entire contents of the#contact_formdiv (remember I said we would be needing that div) with the following line:

          $('#contact_form').html("<div id='message'></div>");

This replaces all the content inside the contact form, using jQuery'shtml() function. So instead of a form, we now have a newdiv with an id ofmessage. Next, we fill that div with an actual message: anh2 sayingContact Form Submitted:

          $('#message').html("<h2>Contact Form Submitted!</h2>")

We'll add even more content to the message with jQuery'sappend() function, and to top everything off, we add a cool effect by hiding the message div with the jQueryhide() function, and then fade it in with thefadeIn() function:

          .append("<p>We will be in touch soon.</p>")   .hide()   .fadeIn(1500, function() {     $('#message').append("<img id='checkmark' src='images/check.png' />");   });

So the user ends up seeing the following after they submit the form:

Conclusion

By now, I think you will have to agree that it's incredibly easy to submit forms without page refresh using jQuery's powerfulajax() function. Just get the values in your JavaScript file, process them with theajax() function, and returnfalse. You can process the values in your PHP script just like you would any other PHP file, the only difference being that the user does not have to wait for a page refresh—it all happens silently in the background.

So if you have a contact form on your website, a login form, or even more advanced forms that process values through a database and retrieve the results, you can do it all easily and efficiently with AJAX.

Learn JavaScript With a Free Course

If you want to master JavaScript, be sure to check out our free course to learn the complete A-Z of modern JavaScript fundamentals.

In this course, you'll learn all of the essential concepts of the JavaScript language. That's right: all of them! Including the most important recent improvements to the language, in JavaScript ES6 (ECMAScript 2015) and JavaScript ES7 (ECMAScript 2016).

You'll start with the very fundamentals of the language: variables and datatypes. Then in each lesson you'll build knowledge, from data structures like arrays and maps to loops, control structures, and functions. Along with the basics of the language, you'll also learn some key built-in APIs for manipulating data, AJAX, and working with the web browser DOM. Finally, you'll get a look at some of the most powerful and widely used web APIs that are supported by all modern browsers.

Did you find this post useful?

Eric is a Freelance Web Developer, Oil Pastels Artist, and committed coffee drinker. :D

ulloalandand1971.blogspot.com

Source: https://code.tutsplus.com/tutorials/submit-a-form-without-page-refresh-using-jquery--net-59

Share this post