Untitled

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Progress</title>
    <script type="text/javascript" rel="script" src="javascript/jquery-3.3.1.js"></script>


    <style>
        .container{
            width: 500px;
            margin: auto;
        }
        .progress{
            margin: 0;
            padding: 0 ;
            background: red;
            width: 0;
            height: 30px;
        }
    </style>
</head>
<body>

<div class="container">
    <div>
        <button id="minus" style="padding-right: 10px">-10</button>
        <button id="plus">+10</button>
    </div>
    <div id="full-progress" style="padding: 0; width: 500px">
        <div class="progress">
        </div>
    </div>
</div>

<script>
    $(document).ready(function () {

        $('#plus').click(function () {
            let progress = $('.progress');
            let fullProgress = $('#full-progress');

            if(!(progress.css('width') == fullProgress.css('width'))){
                progress.css('width', '+=10%');
            }

        });
        $('#minus').click(function () {
            let progress = $('.progress');
            let fullProgress = $('#full-progress');

            if(!(progress.css('width') == "0px")){
                progress.css('width', '-=10%');
            }
        });

    })
</script>
</body>
</html>