Regular Expression for not allowing two consecutive special characters

Question

What i am trying to do is to not allow two consecutive special characters like &* or *$ or &&, but it should allow special characters in between strings like Hello%Mr&.

What i have tried so far:

^(([\%\/\\\&\?\,\'\;\:\!\-])\2?(?!\2))+$

Answer 1

^(?!.*[\%\/\\\&\?\,\'\;\:\!\-]{2}).*$

The idea is to use a negative lookahead ((?!)) to verify that nowhere in the string (.*) are there two consecutive "special" characters ([...]{2}). Afterwards, you just match the entire string (.*).