SyntaxError: numbers out of order in {} quantifier.

SyntaxError: Invalid regular expression: /1{2,1}/: numbers out of order in {} quantifier (V8-based)
SyntaxError: numbers out of order in {} quantifier. (Firefox)
SyntaxError: Invalid regular expression: numbers out of order in {} quantifier (Safari)

The {n,m} syntax in a regular expression is used to specify that the preceding item is to be matched at least n times, but not more than m times. If m is less than n, the quantifier is nonsensical because, for example, a character cannot appear at least 2 times but not more than 1 time. Therefore, an error is thrown.

• Regular expressions
• Quantifier: *, +, ?, {n}, {n,}, {n,m}