Let's talk about the differences and relationships between JavaScript and HTML

This article brings you relevant knowledge about javascript, which mainly introduces the related issues about the relationship and difference between JavaScript and html. HTML is an identifying language. JavaScript is an interpreted scripting language. Let’s take a look at it. I hope it will be helpful to everyone.

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What is HTML?

HTML is called HyperText Markup Language (HyperText Markup Language), which is a marking language. It includes a series of tags. These tags can unify the document format on the network and connect scattered Internet resources into a logical whole. [Recommended: HTML Online Manual]

HTML text is descriptive text composed of HTML commands. HTML commands can describe text, graphics, animations, sounds, tables, links, etc.

Hypertext is a way of organizing information that associates words and graphics in the text with other information media through hyperlinks. These interrelated information media may be in the same text, may be other files, or may be files on a computer that are geographically distant. This way of organizing information connects information resources distributed in different locations in a random manner, making it easier for people to find and retrieve information.

What is JavaScript?

JavaScript is an advanced, interpreted, literal scripting language. It is a prototype-based, function-first language. It is a multi-paradigm language. It supports object-oriented programming and imperative programming. and functional programming.

Javascript is classified as a literal translation language because mainstream engines load the code and interpret it every time it is run.

JavaScript has been standardized as a language by ECMA (European Computer Manufacturers Association) through ECMAScript. It is used by most websites in the world and is also supported by the world's mainstream browsers (Chrome, IE, Firefox, Safari, Opera).

JavaScript is a network scripting language that has been widely used in Web application development. It is often used to add various dynamic functions to web pages to provide users with smoother and more beautiful browsing effects.

The difference between HTML and JavaScript

1. Essential difference

HTML is a markup language without logical functions; JavaScript is a scripting language , like c and java, has logical functions.

2. Usage difference

HTML provides static content on the web page. JavaScript adds dynamic functionality to static web pages.

html is the basis for web page production. What is produced is static, and js is a script. It is combined with html to generate a more powerful web page. Can handle some dynamic logic problems.

JavaScript can be embedded in HTML, but HTML cannot be embedded in JavaScript.

javaScript is case-sensitive, but html is not very strict.

3. Standardization difference

HTML is based on W3C and WHATWG standards, and JavaScript is based on ECMA standards.

4. Compatibility difference

HTML is cross-browser compatible, which means it is compatible with all versions of all web browsers, including modern browsers. All browsers, whether old or new, handle unrecognized elements as inline elements by default, which makes it easy for older web browsers to handle unknown HTML elements.

On the other hand, JavaScript lacks cross-browser compatibility, which makes some functions incompatible with certain browsers.

How to associate JS with HTML

Note: A separate js file needs to be imported into the html file before the code can take effect. For methods, see this link link

1.js operates html components through id

Code example

<!--html代码-->
<input type="text" id="myqr">//设定组件的id为“myqr”

Use the document.getElementById() function to combine the component with js variable association

Then operate the corresponding attribute of the component through (the variable.property name)

//js代码
var love = document.getElementById('myqr');//通过id获取对应组件的索引
var a = love.value;//将组件的value属性值赋给变量a
love.value = "love you so much";//将组件的输入内容设为该字符串
love.type = "file";//将组件的输入类型设为文件

2. The JS function responds to the button through the onclick attribute

<!--html代码-->
<button onclick="myqr()">完成</button>

Set the onclick attribute of the button component to myqr() and the myqr() function of js will be triggered when the button is clicked

//js代码
function  myqr(){
   alert("love you so much");
}

[Related recommendations: javascript video tutorial, web front end】

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