midas.visualize.switchRenderer = function (first) {
    'use strict';
    if (midas.visualize.renderers.js === undefined) {
        midas.visualize.renderers.js = new JavaScriptRenderer("jsRenderer", "/PWService");
        midas.visualize.renderers.js.enableWebSocket(paraview, 'ws://' + json.visualize.hostname + ':' + json.visualize.wsport + '/PWService/Websocket');