In my CMS, I wanted to disallow any string which contains double quote " for certain fields.
Luckily it allows me pass a Regex to valid it. To do that I needed to:
- ^ matches the begining of the string;
- $ matches the end of the the string;
- (?!") is a negative lookahead, in other words, it matches double quotes but negate it (don't pick up);
- ( .)* matches everything else except the previous match (double quote)
So if I type double quote in my field, it won't allow me because the regex returns false:
var first = 'hey you'; var second = 'what can I do "for you"'; var regex = /^((?!").)*$/gim; console.log(first.match(regex)); // ["hey you"] console.log(second.match(regex)); // null <- not valid