What are the benefits of including 'use strict' at the beginning of a JavaScript source file?

The use strict directive is new in JavaScript 1.8.5 (ECMAScript 5). It is not a statement, but a literal expression, ignored by earlier versions of JavaScript. The short answer here is that use strict is a way to voluntarily enforce stricter parsing and error handling on your JavaScript code at runtime. Code errors that would otherwise have been ignored or would have failed silently will now generate errors or throw exceptions.

What is CSS?

Cascading Style Sheets (CSS) is a style sheet language used to set the visual style of web pages. Usually, it is describing the presentation of a document written in HTML, although it can be used to set styles of document written in any markup language (e.g. XML). Along with JavaScript and HTML, CSS is a cornerstone technology, used to create visually engaging, dynamic web pages and user interfaces for web applications.

What is SQL?

SQL stands for Structured Query Language. Basically, SQL is used to communicate with and manipulate a database. According to ANSI (American National Standards Institute), it is the standard language for relational database management systems. The scope of SQL includes data insert, query, update and delete, schema creation and modification, and data access control.

What is JavaScript?

JavaScript is one of the three pillars of modern web development along with HTML and CSS. The majority of websites employ it and it is supported by all modern web browsers. It is a high-level, multi-paradigm, dynamic, untyped, object-oriented (prototype-based), imperative and interpreted programming language.