Why is RegExp.test() not consistent?

Question

I do not understand why the javascript RegExp.test() method do no return the same result every time I call it.

Given the following javascript variables<

Answer 1

That's because you use the g flag. It turns the regexp object into an iterator, whose state changes with each call.

You don't need the g flag here, so just remove it :

var regexo = new RegExp('^'+opener+'$');