Being aware of the front-end-technologies can help testers to add valuable inputs from the overall product experience perspective.
JavaScript
Commonly used to create interactive effects within web browsers.
HTML / HTML5
Offers building blocks to all websites, specifically text and images.
Angular JS
A structural framework for dynamic web apps.
NodeJS
Open-source, cross platform JavaScript run-time environment that executes JS code server-side
React JS
Creates large web apps that can change data without reloading the page
jQuery
A JavaScript library that allows web developers to add extra functionality to their websites.
CSS
Used to define styles for web pages including the design layout and variations in display for different devices and screen sizes.
Ajax
For creating better, faster and more interactive web applications with the help of XML, HTML, CSS and JavaScript.