code: function onGlobalMessage(event) {                                                                       // 91
      // This will catch all incoming messages (even from other                                             // 92
      // windows!), so we need to try reasonably hard to avoid letting                                      // 93
      // anyone else trick us into firing off. We test the origin is                                        // 94
      // still this window, and that a (randomly generated)                                                 // 95
      // unpredictable identifying prefix is present.                                                       // 96
      if (event.source === global &&                                                                        // 97
          isStringAndStartsWith(event.data, MESSAGE_PREFIX)) {                                              // 98
        var index = event.data.substring(MESSAGE_PREFIX.length);                                            // 99
        try {                                                                                               // 100
          if (funcs[index])                                                                                 // 101
            funcs[index]();                                                                                 // 102
        }                                                                                                   // 103
        finally {                                                                                           // 104
          delete funcs[index];                                                                              // 105
        }                                                                                                   // 106
      }                                                                                                     // 107
    }
docs: 89 90