What is the basic knowledge of Javascript_

what is JavaScript
JavaScript is a client-side scripting language based on object and event-driven.
JavaScript was originally designed to verify the correctness of HTML form input.
JavaScript originated in the LiveScript language of Netscape Company.

The history of JavaScript
JavaScript originally originated from the LiveScript language, when the internet began to become popular, more and more Web sites began to use HTML forms to interact with users, but form interaction has become a major bottleneck in the network development (users are always painfully waiting for data to be transferred to the server side of the test, and return the correct , only form detection produces multiple client-side interactions with the server. So Netscape introduced the LiveScript language, and finally Netscape and Sun named LiveScript JavaScript (Java was a fashionable internet noun), and then Microsoft began its ambitious browser program, And the introduction of JScript, there are several similar JavaScript languages on the network, but there is no uniform characteristics and syntax (JavaScript development was considered a nightmare, so many programmers are not optimistic about JavaScript). Eventually JavaScript was submitted to the European Computer Manufacturers Association (ECMA) as a neutral ECMA began the path of standardizing scripting languages and naming it ECMAScript.

the composition of JavaScript
Complete JavaScript consists of ECMAScript (syntax), Browser Objects (DOM, BOM) (attributes).


The illustration above is a composition diagram of JavaScript, and the arrows represent the calling relationship


A few questions
Why do you want to learn JavaScript?
Because you have no choice but to use JavaScript to control all the common 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 very good, so we have to learn:
is JavaScript the same as Java?
JavaScript has nothing to do with Java, they are two languages in themselves, taking the same name, mostly for business reasons.

JavaScript is a client-side scripting language
Java is a server-side language. (It's a sun company's product.)
is JavaScript hard to learn?
Easy, JavaScript entry is simple, you can learn JavaScript in primary school math, but you have to learn the HTML language first.

what can JavaScript do?
JavaScript detects the correctness of forms, implements Ajax, reads, writes, changes the architecture Dom of HTML pages, responds to events, detects devices used by viewers, produces cool, awesome web effects, DHTML, and so on.
What software is needed to learn JavaScript?
As long as Windows Notepad and the browser (Ie,firefox,opera) is OK, but I recommend you use a powerful notepad++ editor.