Create a SPA with PHP

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Today, we will create an SPA with PHP. Our output will look like this. (The GIF, a bit slow?)
9590e930-f29d-4328-a9b9-b87366dd59fe

Getting started

Our directory structure will be like this.

spa
 ┣ about.php // A page
 ┣ footer.php  // Footer
 ┣ header.php  // Header
 ┣ index.php // The index page
 ┣ instantclick.min.js  // Our secret weapon
 â”— utils.php // Some utils

Now create those files. Then, we'll make the header and footer templates.
header.php

<header>
    <h1>
        PHP SPA
    </h1>
</header>

footer.php

<footer>
    <p>
        Acme Inc
    </p>
</footer>

Now put that code in the correct PHP files (header.php, footer.php)
After that, we will make our utils in utils.php.
The first function is a utility for showing the title and adding styles.

<?php
function head($title, $activepage)
{
    ob_start(); ?>
    <!DOCTYPE html>
    <html lang="en">

    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title><?= $title; ?></title>
        <style>
            * {
                font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            }

            .nav {
                display: flex;
                width: max-content;
            }

            .item {
                flex: 1;
                margin-right: 10px;
                background: #f6f6f6;
                font-size: 18px;
                padding: 7px 18px;
                border-radius: 4px;
                text-decoration: none;
                color: #504f4f;
            }

            .item:hover {
                background: #e7e7e7;
            }

            .item.active {
                background: #d9e8ff;
                color: #1f57dd;
            }

            .item.active:hover {
                background: #c7ddff;
            }
        </style>
    </head>

    <body>

    <?php
        require_once 'header.php';
        $pages = array("index", "about");
        echo "<div class='nav'>";

    foreach ($pages as $page) {
        if ($page == $activepage) {
            echo "<a href='$page.php' class='item active'>$page</a>";
        } else {
            echo "<a href='$page.php' class='item'>$page</a>";
        }
    }

    echo "</div>";
    return ob_get_clean();
}

Then we create another function to show the footer and require the javascript files.

function footer()
{
    ob_start(); 
    require_once 'footer.php';
?>
        <script src="instantclick.min.js"></script>
        <script data-no-instant>
            InstantClick.init();
        </script>
    </body>

    </html>
<?php
    return ob_get_clean();
}

Now, we add these two functions to utils.php.

Adding some pages

Now we add some pages so we can test our SPA.
index.php

<?php
require_once 'utils.php';
echo head('Home', 'index');
?>

<h1>
    Home!
</h1>
<p>
    Welcome to my website!
</p>

<pre id="javascript"></pre>

<style>
    h1 {
        color: #4a4f56;
    }
</style>

<script>
    document.getElementById('javascript').innerHTML = 'Hey! I\'m JavaScript!';
</script>

<?php
echo footer();

about.php

<?php
require_once 'utils.php';
echo head('Home', 'about');
?>

<h1>
    About!
</h1>
<p>
    Contact
</p>

<div id="form">
    <textarea id="message" cols="30" rows="10"></textarea>
    <button id="submit">
        Submit
    </button>
</div>

<style>
    #form {
        max-width: 400px;
    }

    #message {
        width: 100%;
        height: 100px;
        border: 1px solid #ccc;
    }

    #submit {
        padding: 10px 20px;
        margin-top: 10px;
        background-color: #4a4f56;
        color: #fff;
        border: none;
        border-radius: 100px;
    }
</style>

<script>
    document.getElementById('submit').onclick = _ => alert("Message: " + document.getElementById('message').value);
</script>

<?php
echo footer();

Now let's see what we've got!

image

Nice (for a demo ?). Now we'll add our SPA functionality. We will use the Instantclick library for this. Just download this file and replace the instantclick.min.js file in our project! That's all you need to do. You now have created an SPA with PHP. You can check the source code here.