Function beforeUnloadEventHandlerFunc

src/lib/libhtml5.js:2039–2041

(e)

  $registerBeforeUnloadEventCallback__deps: ['$JSEvents', '$findEventTarget'],
  $registerBeforeUnloadEventCallback: (target, userData, useCapture, callbackfunc, eventTypeId, eventTypeString) => {
    var beforeUnloadEventHandlerFunc = (e) => {
      // Note: This is always called on the main browser thread, since it needs synchronously return a value!
      var confirmationMessage = {{{ makeDynCall('pipp', 'callbackfunc') }}}(eventTypeId, 0, userData);

      if (confirmationMessage) {
        confirmationMessage = UTF8ToString(confirmationMessage);