Working with regular expressions I’m also going to cover how to work with regular expressions in JavaScript, though the concepts learned here apply to other languages as well.

Regular expressions are patterns that provide a powerful way to search and replace in text. In JavaScript, they are available via the RegExp object, as well as being integrated in methods of strings.

brackets in regular expression If you don't use square brackets, the meaning of the code changes. For example, without the square brackets, the code /\d./ will match any character that is followed by ...