tion.x + deltaX}px`;
        box.style.top = `${position.y + deltaY}px`;
      }

      function addLog(message){
        var messageDiv = document.createElement("div");
        var textContent = document.createTextNode(message);
        messageDiv.appendChild(textContent);
        logDiv.appendChild(messageDiv);
      }

      function handle_pointerdown(e){
        box.setPointerCapture(e.pointerId);
        if(window.promise_test){
          current_test.step(function(){
            // once receiving a p