How to hide and show the input element of the form in HTML

Question

Suppose I have a form which has some file fields:

        <form action="" method="post" enctype="multipart/form-data" id="form">
        <h3>Ask </h3>
        <p></p>
            <div>
            <p><label for="id_title">Topic</label>:<p>
            <p><input id="id_title" type="text" name="title" maxlength="300" /><p>
            </div>
            <div>
            <p><label for="id_pic">Picture</label>:<p>
            <p><input type="file" name="pic" id="id_pic" /><p>
            <p><button type="button">Add more pictures</button></p>
            </div>
            <div>
            <p><label for="id_pic_1">Picture 1</label>:<p>
            <p><input type="file" name="pic_1" id="id_pic_1" /><p>
            </div>
            <div>
            <p><label for="id_pic_2">Picture 2</label>:<p>
            <p><input type="file" name="pic_2" id="id_pic_2" /><p>
            </div>
            <div>
            <p><label for="id_pic_3">Picture 3</label>:<p>
            <p><input type="file" name="pic_3" id="id_pic_3" /><p>
            </div>
            <div>
            <p><label for="id_pic_4">Picture 4</label>:<p>
            <p><input type="file" name="pic_4" id="id_pic_4" /><p>
            </div>
            <div>
            <p><label for="id_description">Details</label>:<p>
            <p><textarea id="id_description" rows="10" cols="40" name="description"></textarea><p>
            </div>
            <button type="submit">Submit</button>
        </form>

Initially, I would like to hide pic_1, pic_2, pic_3 and pic_4 until user click the button under pic. I think javascript can do that but I am new to javascript.

Can anyone give me some direction?

Thanks.

Answer 1

Short answer

Give your "Add more pictures" button an ID called add-more. Then, add this code to your page right before the </body>:

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script>
$(document).ready(function() {
    // Hide the additional photo uploads
    var $additionals = $("#id_pic_1, #id_pic_2, #id_pic_3, #id_pic_4");
    $additionals.hide();
    // Show more photo uploaders when we click 
    $("#add-more").on("click", function() {
        $additionals.show();
    });
});
</script>

Long answer

jQuery is a JavaScript library that makes these things much easier to deal with. It's so ubiquitous and helpful that some people (myself included, when I was learning) thought that jQuery was JavaScript.

Include a link to it on your page to get jQuery:

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

Before we do anything else, let's give the button an ID so that we can reference it later. Let's call our button add-more.

<button type="button" id="add-more">Add more pictures</button>

Now, let's add some of our own JavaScript to the page. You should probably put this in a separate file, but you can get away with putting the following stuff in <script> tags after the jQuery stuff:

$(document).ready(function() {

    // This code is inside of the "document ready" stuff because it
    // will execute AFTER all of the HTML stuff has been loaded.

    // First, let's find all of the additional things we want to hide
    // initially. We COULD do this with CSS but then browsers without
    // JavaScript couldn't upload more photos.
    var $additionals = $("#id_pic_1, #id_pic_2, #id_pic_3, #id_pic_4");

    // Okay, so now we have all of those in a variable called $additionals.
    // Variables don't have to start with a $, but because jQuery uses that,
    // I like to prefix my jQuery-selected elements with a dollar sign.
    // Let's hide them now!
    $additionals.hide();

    // When we click the button with the ID "add-more", show the other stuff.
    $("#add-more").on("click", function() {
        $additionals.show();
    });

});

Answer 2

Use CSS to hide the images

.hide-me {
    display: none;
 }

Now include jQuery between the like this:

 <script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

Now between script tags (preferably at the end of your page):

<script>
$(document).on('ready', function () {

    $(.hide-me').show();

});
<script>

This just tells jQuery once the page is loaded you want to show the images with the class .hide-me