What is JavaScript?

What is JavaScript?
JavaScript is an object-and event-driven client scripting language.
JavaScript was originally designed to verify the correctness of HTML form input.
JavaScript originated from Netscape's LiveScript language.

JavaScript history
JavaScript originally originated from the LiveScript language. When the Internet became popular, more and more websites began to use HTML forms to interact with users, however, form interaction has become a major bottleneck restricting the development of the network (users are always waiting for the data to be transmitted to the server for detection, and the returned results are correct, just form detection, the client interacts with the server multiple times ). As a result, Netscape launched the LiveScript language. Finally, Netscape and Sun named LiveScript JavaScript (JAVA was a very fashionable Internet term at the time). Then Microsoft began its ambitious browser program, JScript was launched, so several similar JavaScript languages appeared on the Internet, but there was no unified features and syntax (JavaScript development was seen as a nightmare at that time, therefore, many programmers are not optimistic about JavaScript ). Finally, JavaScript was submitted to the European Computer Manufacturers Association (ECMA). As a neutral ECMA, it began to standardize the scripting language and named it ECMAScript.

Composition of JavaScript
The complete JavaScript is composed of ECMAScript (syntax), Browser Objects (DOM, BOM) (features.


Is a JavaScript composition graph, the arrow represents the call relationship


Several Questions
Why JavaScript?
Because you have no choice, only JavaScript can control all commonly used browsers, and JavaScript is one of the most important programming languages in the world, learning web technology must learn JavaScript.
JavaScript is a beautiful language, it is good, so we need to learn :)
Is JavaScript the same as Java?
Javascript has nothing to do with java. They are actually two languages and get similar names, mainly for commercial reasons.

Javascript is a client scripting language.
Java is the server language. (It is a product of SUN .)
Is JavaScript hard to learn?
It is not difficult. JavaScript is easy to get started. You only need to learn JavaScript in elementary school mathematics, but you must first learn the HTML language.

What can JavaScript do?
JavaScript can detect the correctness of forms, implement Ajax, read, write, and change the DOM architecture of HTML pages, respond to events, and detect devices used by viewers, produce cool and dazzling web page effects such as DHTML.
What software is required to learn JavaScript?
You only need windows Notepad and browsers (IE, Firefox, and Opera), but I recommend you use the powerful Notepad ++ editor.