  var groups = new vis.DataSet();
    groups.add(groupData);

    var graph2d = new vis.Graph2d(container, dataset, groups, options);
    updateStyle();

    function updateStyle() {
        groupData.style = "";
        groupData.style += document.getElementById("color").value;
        groupData.style += document.getElementById("line").value;
        groupData.style += document.getElementById("thickness").value;

        groupData.options.drawPoints = {};
        groupData.options.drawPoints.styles = "";
 