在所有现代浏览器中，javascript正则表达式中的花括号处理是否相同？

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