Search in an array (set) in JavaScript

Recently solved the problem when it was necessary to determine whether a certain (string) value falls into the set of valid values.
In JavaScript 1.6, there is an indexOf method of an Array object to search in an array, but this method is not supported in Internet Explorer. For IE, this method is implemented by looping through an array.
But since the order of the elements was not important and every millisecond was counting, I compared the performance of loop enumeration in an array with other search options (without enumeration).

And the search options without searching are as follows:

1. Gluing an array into a string and search in a string
   

   if (myarray.join().search("Строка поиска") != -1) { ... }

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   When using this method, it is necessary to take into account the uniqueness of the occurrence of the search substring in the string glued from the array. To do this, you can, for example, use gluing characters that a priori do not appear on the line:
   

   if (("#" + myarray.join("#,#") + "#").search("#Строка поиска#") != -1) { ... }

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2. Using an object instead of an array, “hash keys” are hash keys
   

   if ("Строка поиска" in myarray) { ... }

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To evaluate the performance of each of the three search methods, I created a test page on which 100,000 lines of the form "StringN" are created, where N is the line number, and then the string "String60000" is searched.
It turned out that the in operator works almost instantly (the runtime is always 0), even in IE6!

Test Results (Celeron 2.4)

Browser	in	String.search	Array.indexOf
IE6	zero	94	2859
IE7	zero	125	390
Ff2	zero	2016	31
Ff3	zero	71	3
O9	zero	281	47
Safari3	zero	188	31

Search time in ms.