Question 1

What regex flavor is this?

Accepted Answer

JavaScript RegExp in the tab. Not PCRE and not Python.

Question 2

Does my text leave the browser?

Accepted Answer

No. Testing stays in the tab.

Question 3

Which flags work?

Accepted Answer

g, i, m, s, u, and y.

Question 4

Can I find and replace in files?

Accepted Answer

No. Paste a sample string. This is not a disk search.

Question 5

Why does a Python pattern fail here?

Accepted Answer

The flavors differ. Re-test in Python if that is the runtime.

Question 6

What does the g flag do?

Accepted Answer

It finds every match, not only the first.

Question 7

What does the y flag do?

Accepted Answer

Sticky. The next match must start at lastIndex.

Question 8

Are matches stored?

Accepted Answer

No. Close the tab and the sample is gone.

Question 9

Can I use this as a validator in production?

Accepted Answer

It is a tester. Copy the pattern into your own code after it behaves.

Question 10

Does this work offline after load?

Accepted Answer

Yes.

Question 11

Is this the same as Word Counter?

Accepted Answer

No. This finds pattern matches. Word Counter splits on whitespace.

Regex Tester - JavaScript Regular Expressions in Tab