I Have Some Code But Its Not Working Please Help Me

Question

function create() {
       var hdrwdth = 0;
       var t = '';
       t += "<div class='topnav'><div class='title'>titleText</div></div>";
       $('#div1').append(t);
       }

<div id="div1"></div>

.topnav {
    background-color: dodgerblue;
    width: 100%;
    height: 30px;

    z-index: 1000;
    position: relative;
    border: 1px solid #CCCCCC;
}