Apparently regular expressions with the g modifier are stateful. See for yourself.
<button id='bad'>Wait, WHAT?</button>
stateful = /button/ig;
bad.onclick = function (e) {
alert(stateful.test(e.target.tagName));
};
The button alternates between alerting true and false in Google Chrome 38.0.2125.122, and also on Firefox 31.
As it turns out, this is the “expected” behavior. I did not expect that. Regular expressions with the g modifier on them will keep track of the lastIndex where a match occurred, even across calls to .test.
You can check out the live example on CodePen, too.
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