window.onload = function() {
    var settings = {
      tl: { radius: 16 },
      tr: { radius: 16 },
      bl: { radius: 16 },
      br: { radius: 16 },
      antiAlias: true
    }

    var divObj = document.getElementById("wrapper");
    curvyCorners(settings, divObj);

    // or, equivalently:
    curvyCorners(settings, '#wrapper');
  }