Why do two regex literals in my Javascript vary on a property? -

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i read in javascript: parts douglas crockford javascript regular expression literals share same object. if so, how come these 2 regex literals vary in lastindex property?

var = /a/g; var b = /a/g;  a.lastindex = 3; document.write(b.lastindex);​

js fiddle

0 outputted opposed 3.

section 7.8.5 of ecmascript documentation makes quite clear 2 different objects:

7.8.5 regular expression literals
regular expression literal input element converted regexp object (see 15.10) each time literal evaluated. 2 regular expression literals in program evaluate regular expression objects never compare === each other if 2 literals' contents identical. regexp object may created @ runtime new regexp (see 15.10.4) or calling regexp constructor function (15.10.3).


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