Regex: only alphanumeric but not if this is pure numeric

Question

For instance:

\'1\'     => NG
\'243\'   => NG
\'1av\'   => OK
\'pRo\'   => OK
\'123k%\' => NG

I tried with

Answer 1

Use

/^(?![0-9]*$)[a-zA-Z0-9]+$/

This expression has a negative lookahead to verify that the string is not only numbers. See it in action with RegExr.