Can someone give me an example JavaScript RegEx to invalidate 2 repeating characters from being entered

I need a RegEx to trigger a validation message when a user enters 2 r开发者_如何学Goepeating characters.

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Well

var repeats = /(.)\1/;

will match any string with a character repeated in it.

Thus

if (repeats.test("hello")) alert("true because of the two 'l' characters");

and

if (!repeats.test("frederick the great")) alert("test fails because no characters repeat");