Function handleScanStart

internal/driver/html/common.js:111–117

(e)

  }

  function handleScanStart(e) {
    if (e.button != 0) return; // Do not catch right-clicks etc.
    setMode(MOUSEPAN);
    panStart(e.clientX, e.clientY);
    e.preventDefault();
    svg.addEventListener('mousemove', handleScanMove);
  }

  function handleScanMove(e) {
    if (e.buttons == 0) {