The Tor Browser / file revision

 /// Copyright (c) 2012 Ecma International.  All rights reserved. 

 /// Ecma International makes this code available under the terms and conditions set

 /// forth on http://hg.ecmascript.org/tests/test262/raw-file/tip/LICENSE (the 

 /// "Use Terms").   Any redistribution of this code must retain the above 

 /// copyright and this notice and otherwise comply with the Use Terms.

 /**

  * @path ch11/11.4/11.4.1/11.4.1-5-1.js

  * @description delete operator returns false when deleting a direct reference to a var

  */

 function testcase() {

   var x = 1;

   // Now, deleting 'x' directly should fail;

   var d = delete x;

   if(d === false && x === 1)

     return true;

  }

 runTestCase(testcase);