By far, one of the most common uses for regular expressions on the frontend is for use with user submitted forms, so this is what we will be building. The form we will be building will have all the common fields, such as name, e-mail, website, and so on, but we will also experiment with some text processing besides all the validations.
jQuery validation : Refer to http://jqueryvalidation.org/
Parsely.js: Refer to http://parsleyjs.org/
Even the most popular frameworks support the usage of regular expressions with its native validation engine, such as AngularJS (refer to http://www.ng-newsletter.com/posts/validations.html).