Python Learning (21)--JavaScript on the front

Reprinted from Http://www.cnblogs.com/liwenzhou/p/8004649.html

First, JavaScript overview of the history of 1.JavaScript

• 1992 Nombas developed the embedded scripting language for C-minus-minus (c--) (originally bundled in Cenvi software). Rename it scriptease. (The language that the client executes)
• Netscape (Netscape) received Nombas's philosophy, (Brendan Eich) developed a set of Netscape scripting languages in its Navigator livescript 2.0 product. Sun and Netscape are done together. And then the name is JavaScript.
• Microsoft then emulated a JavaScript clone called JScript in its IE3.0 product.
• To unify the three, the ECMA ( European Computer Manufacturing Association) defines the ECMA-262 specification. The International Organization for Standardization (ISO/IEC) also adopted ECMAScript as the standard (iso/iec-16262). Since then, Web browsers have struggled (albeit with varying degrees of success and failure) to ECMAScript as the basis for JAVASCRIPT implementations. ECMAScript is the norm.

2.ECMAScript

Although ECMAScript is an important standard, it is not the only part of JavaScript, and certainly not the only one that is standardized. In fact, a complete JavaScript implementation is made up of the following 3 different parts:

• Core (ECMAScript)
• Document Object Model (DOM) Documents object models (consolidated js,css,html)
• Browser object models (BOM) Broswer object Model (integrated JS and browser)
• The vast majority of Javascript in development is object-based. It is also object-oriented.

To put it simply, ECMAScript describes the following:

• Grammar
• Type
• Statement
• Key words
• Reserved words
• Operator
• Object (encapsulates inherited polymorphism) object-based language. Use an object.

Second, JavaScript introduction method1.write code inside the script tag

<script>  //  Write your JS code here </script>

2. Introduction of additional JS files

<script src= "Myscript.js" ></script>

Iii. JavaScript Language Specification 1. Notes

// This is a single-line comment /* This is a multi-line comment */

2. Terminator

The statements in JavaScript are terminated with a semicolon (;).

Python Learning (21)--JavaScript on the front