<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <div class="desktop">
            <div class="iframe-wrapper">
                <iframe frameborder="0" scrolling="no"></iframe>
            </div>
            <i class="fa fa-desktop"></i>
        </div>

        <div class="tablet">
            <div class="iframe-wrapper">
                <iframe frameborder="0" scrolling="no"></iframe>
            </div>
            <i class="fa fa-tablet"></i>
        </div>

        <div class="mobile">
            <div class="iframe-wrapper">
                <iframe frameborder="0" scrolling="no"></iframe>
            </div>
            <i class="fa fa-mobile"></i>
        </div>

        <h1>Test your website<br><strong>responsivity</strong></h1>
    </body>
</html>

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title></title>
        <script src="./functions.js"></script>
        <link rel="stylesheet" href="./style.css">
    </head>
    <body>
        <div class="desktop">
            <div class="iframe-wrapper">
                <iframe frameborder="0" scrolling="no"></iframe>
            </div>
            <i class="fa fa-desktop"></i>
        </div>

        <div class="tablet">
            <div class="iframe-wrapper">
                <iframe frameborder="0" scrolling="no"></iframe>
            </div>
            <i class="fa fa-tablet"></i>
        </div>

        <div class="mobile">
            <div class="iframe-wrapper">
                <iframe frameborder="0" scrolling="no"></iframe>
            </div>
            <i class="fa fa-mobile"></i>
        </div>

        <h1>Test your website<br><strong>responsivity</strong></h1>
    </body>
</html>

Include js and css files
Include js and css files
