I just need to validate 2 strings in javascript. One of them must contain only 0 or more open parenthesis ( . The other must contain only 0 or more close parenthesis ) . This means only those characters are allowed in each value. After spending a lot of time trying to understand the regex, I can't find a way to achieve this. With the escape characters I make a mess of the regex function. This is what I thought: /\(*/ Could anyone help me?