JavaScript is a scripting language built into the browser. That is to say, the browser has a built-in JavaScript engine and provides various interfaces so that JavaScript scripts can control various functions of the browser; once a web page has embedded JavaScript Script, the browser will execute the script when loading the web page.
The operating environment of this article: Windows 7 system, javascript version 1.8.5, DELL G3 computer
Is JavaScript built-in in the browser?
JavaScript is the browser’s built-in scripting language. In other words, the browser has a built-in JavaScript engine and provides various interfaces so that JavaScript scripts can control various functions of the browser. Once a web page has a JavaScript script embedded in it, when the browser loads the web page, it will execute the script to achieve the purpose of operating the browser and achieve various dynamic effects on the web page.
Generally speaking, a complete JavaScript includes the following parts:
ECMAScript, which describes the syntax and basic objects of the language
Document Object Model (DOM), describes the methods and interfaces for processing web content
Browser Object Model (BOM), describes how to interact with the browser Interactive methods and interfaces
The basic characteristics of JavaScript are as follows:
is an interpreted scripting language (code Not precompiled).
Mainly used to add interactive behaviors to HTML pages.
It can be directly embedded in HTML pages, but writing it as a separate js file is beneficial to the separation of structure and behavior.
JavaScript is commonly used to complete the following tasks:
Embed dynamic text in HTML pages
Respond to browser events
Read and write HTML elements
Validate data before it is submitted to the server
Detect visitors’ browser information
Control cookies, including creation and modification
Recommended learning : "javascript video tutorial"
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