gger").style.left = Math.random()*100 + 'px';
      }, 1000)
      document.addEventListener('click', trigger)

      function trigger() {
        var xhr = new XMLHttpRequest()
        xhr.open('GET', '/json')
        xhr.addEventListener('load', function () {
          generateNodes()
        })
        xhr.send()
      }

      // we need to have >30 nodes in the session trace to ensure it actually gets
      // sent, so make some nodes
      function generateNodes() {
        for (var i = 0; i < 31; i++