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What is HTML? What is CSS? What are JavaScript, PHP and MySQL?

What is HTML?

HTML is a static language for text formatting for web pages use. All web pages on the web consists of HTML which is sent to the browser for rendering. Browser interpret the HTML and convert it into colors, fonts and design. HTML is the abbreviation of Hyper Text Markup Language which means a language for writing text contents with non text contents i.e. list, table, alignment etc…
HTML mainly consists from TAGS with some contents inside. i.e. <p>Hello World</p> this tells the browser that there is a paragraph with the sentence “Hello World” inside. Similarly <img src=”http://path/to” /> tells the browser to display an image located at the url http://path/to
HTML has many versions starting from HTML 4.0 which issued at late 1997 until the most recent HTML5.
HTML5 has incorporated many new TAGS and supports a wide range of contents other than images like video and audio.

What is CSS?

CSS is the abbreviation of “Cascaded Style Sheets” and it is a coding method to let the browser knows the design of the HTML contents rendered. The word design here means colors, alignment, spacing, borders, backgrounds, font, width, height, etc… Because there is no code running here, CSS is considered a static language “Not a programming language”.

There are three different ways to embed a style sheet it can be either embedded into the tag, in a separate block in the page or in a separate file.
The syntax for embedding into a tag is as following:-

While the syntax for writing the style sheet into a separate block is just writing all styling enclosed into a style tag.

Last way of writing style sheets is by writing the styles into a separate file with the extension .css then adding the following tag into the head section.

The following image depicts a styling for h1 and body elements. With this style sheet any h1 in the web page will be colored white with orange background.

What is Javascript?

Javascript is a programming language that can be embedded or loaded alongside the web page. The code is downloaded and run by the browser. With javascript you can do any processing, do calculations or access cookies. However you can not access user data or files located on his PC. Also access to network is limited i.e. you can not run a server on the user machine.
With web being evolved to Web 2.0 more dynamic contents are incorporated into web pages. Starting from drop down menus, sliders, image galleries and more… Every thing here make use of javascript to provide the dynamics of the web page. Since both HTML and CSS are just static languages, here JavaScript comes into use. With Javascript you can load contents dynamically, do some calculations and change existing text and more…
Javascript alike CSS can either be embedded into the same page or included from external file.


What is PHP?

With javascript you can create dynamic contents, but it will lacks persistency and security. With javascript you can store data only in cookies which can be wiped out either when expired or by the user. Also cookies can be accessed by any application running on the user side which is considered insecure. So to store persistent data securely like user information another medium is required. Here PHP comes into play. PHP is one of many “Server Side” programming languages however it is the most popular one. A server side means the code run on the server side before sending the page contents to the user browser. With PHP you can run code that no one can access or inspect (Javascript code can be viewed or tempered by the user) because PHP code itself is not sent to the browser but it is run instead and its output is sent to the browser.

What is MySQL?

While you can use files to store your data but it is not good idea especially if you want functionalities like user search or reordering. Here a DBMS (Database Management Systems) comes into hand. With MySQL which is a freely distributed open source DBMS you can insert, update or query data using the standard SQL statements.

The following image is an example ER diagram which depicts a sample database with multiple tables liked together.

Check Database Explanation to know more info.

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