Web fundamentals such as HTML, JavaScript, and CSS
CSS preprocessors such as Sass or LESS
JavaScript frameworks such as AngularJS, React, or Ember etc., or JS-based build tools like Grunt, Gulp, and Bower
Libraries like jQuery or Backbone.js
Front-end (CSS) frameworks such as Foundation or Bootstrap
AJAX
Back-End
API design and development
CRUD (Create, Read, Update, Delete)
RESTful Services
Web fundamentals such as HTML, JavaScript, and CSS
Server-side languages such as PHP, Java, JavaScript, and .Net
Database technologies such as MySQL, Oracle, PostgreSQL, and MongoDB.
Web server technologies such as Node.js, J2EE, Apache, Nginx, ISS, etc.
Frameworks related to their server-side language of choice such as Express.js, Ruby on Rails, CakePHP, etc.