Is handling of curly braces in javascript regex is the same across all modern browsers?

Question

Curly braces in JavaScript regex is used to denote quantifiers. So writing

a{2,4}

will match aa, aaa and aaaa. But if you mistype this quantifier like this:

x{1,x}

It will match the literal text "x{1,x}", at least in Firefox.

Is this behavior common to modern browsers?

The ECMA standard prohibits this behavior and requires the escaping of the braces.

(Background: I have to write a parser for javascript regexes at work.)

Answer 1

I don't know for JavaScript and browsers, but this is the behaviour I would have expected and that I have seen in the past in regular expressions.

So I tested different regex engines on their behaviour:

• C#: behaves this way

• Perl: behaves this way

• Python: behaves this way

• PHP: behaves this way

• Java: throws an Exception