HTML 


The definition of HTML is HyperText Markup Language.
Use of HTML 
HTML consists of a series of short codes typed into a text-file by the site author — these are the tags. The text is then saved as a html file, and viewed through a browser, like Internet Explorer or Netscape Navigator. This browser reads the file and translates the text into a visible form, hopefully rendering the page as the author had intended. Writing your own HTML entails using tags correctly to create your vision. You can use anything from a rudimentary text-editor to a powerful graphical editor to create HTML pages.

( for Client side working)

HTML is a computer language devised to allow website creation. These websites can then be viewed by anyone else connected to the Internet. It is relatively easy to learn, with the basics being accessible to most people in one sitting; and quite powerful in what it allows you to create. 


Java Script 


( for Client / server (jquery) side working)
Along with HTML and CSS, JavaScript is essential to front-end web development. A majority of the web’s most popular sites, from Facebook and Twitter to Gmail and YouTube, rely on JavaScript to create interactive web pages and dynamically display content to users.
Although JavaScript is primarily a front-end language run on the browser, it can also be used on the server-side through Node.js to build scalable network applications. Node.js is compatible with Linux, SunOS, Mac OS X, and Windows.
Because JavaScript has a forgiving, flexible syntax and works across all major browsers, it is one of the friendliest programming languages for beginners.


Python 


( for Server side working)
Python is perhaps the most user-friendly programming language of any on this list. It’s often said that Python’s syntax is clear, intuitive, and almost English-like, which, like Java, makes it a popular choice for beginners.
Also like Java, Python has a variety of applications that make it a versatile, powerful option when choosing the best programming language for your use case. If you’re interested in back-end web development, for example, then the open-source Django framework, written in Python, is popular, easy to learn, and feature-rich. Django has been used in the development of some popular sites like Mozilla, Instagram, and Spotify.
Python also has packages such as NumPy and SciPy that are commonly used in the fields of scientific computing, mathematics, and engineering. Other Python libraries such as TensorFlow, PyTorch, scikit-learn, and OpenCV are used to build programs in data science, machine learning, image processing, and computer vision. Python's science and data applications make it a great choice for the academically inclined.


CSS


( for Client side webpage styling )
Stands for "Cascading Style Sheet." Cascading style sheets are used to format the layout of Web pages. They can be used to define text styles, table sizes, and other aspects of Web pages that previously could only be defined in a page's HTML.
Alternate of CSS is bootstrap
Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS- and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.


PHP


( for Server side working)
PHP is a general-purpose scripting language especially suited to web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1994. The PHP reference implementation is now produced by The PHP Group. It is developed from C Language.