Jagascript GET URL Parameter

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>

<span id="devappp"></span>
<script>
function getUrlParameter(sParam)
{
    var sPageURL = window.location.search.substring(1);
    var sURLVariables = sPageURL.split('&');
    for (var i = 0; i < sURLVariables.length; i++)
    {
        var sParameterName = sURLVariables[i].split('=');
        if (sParameterName[0] == sParam)
        {
            return sParameterName[1];
        }
    }
}

var devGet = getUrlParameter('dev');

if(devGet == 'mrz'){
    jQuery('#appp').append(' | Developed by <a href="https://mashiurz.com"><b>Mashiurz</b></a>');
}
</script>