search
HomeWeb Front-endHTML TutorialSolve. Does the ID here have multiple meanings? _html/css_WEB-ITnose

id style attribute

<html>    <head>                <style>            #id320 {                color: red;                            }        </style>    </head>    <body>        <input id="id320" value="0" />        <input id="id320" value="9" />        <button onclick="document.getElementById('id320').value='1'">button</button>    </body></html>

Reply to discussion (solution)

It is generally best not to repeat id

Light Nothing can be seen in this part

What is confusing is
input id="id320"
Is the id here setting the style or defining the logo?

It is generally best not to repeat the id

You can’t tell much from this part alone

What’s confusing is
input id="id320"
What is the id here? Is it setting a style or defining a logo?

You have to look at the context and actual performance of the code to understand the meaning of the code

Of course, sometimes the default and standardized writing methods are not used and will make other readers confused

Just like the code you posted

id is theoretically the only one that represents the whole world

But now there are 2 identical ones hehe

so we can only look at the end of the code Let’s understand the meaning through the performance

If ID is not used in JS, there is no problem in writing like this. Like class, if ID is used in JS, writing in this way will definitely cause problems. Therefore, it is best not to have duplicate IDs.

Can this be understood?

Specification requirements:
ID has only one meaning, which is to uniquely identify an element
The id value must be unique
An id style is only defined for a unique element

When it is not standardized (multiple elements have the same id), the general approach (such as IE/Chrome/Firefox):
getElementById returns the first element found
Set styles for elements with the same id


The id cannot be repeated, it is not a matter of "it's better not to"

It's okay to write duplicates. That's because of the browser's fault tolerance (this is also One of the important reasons why browser vendors collectively boycott xhtml)
But it is wrong to repeat ids grammatically

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
The Future of HTML: Evolution and TrendsThe Future of HTML: Evolution and TrendsMay 13, 2025 am 12:01 AM

The future of HTML will develop in a more semantic, functional and modular direction. 1) Semanticization will make the tag describe the content more clearly, improving SEO and barrier-free access. 2) Functionalization will introduce new elements and attributes to meet user needs. 3) Modularity will support component development and improve code reusability.

Why are HTML attributes important for web development?Why are HTML attributes important for web development?May 12, 2025 am 12:01 AM

HTMLattributesarecrucialinwebdevelopmentforcontrollingbehavior,appearance,andfunctionality.Theyenhanceinteractivity,accessibility,andSEO.Forexample,thesrcattributeintagsimpactsSEO,whileonclickintagsaddsinteractivity.Touseattributeseffectively:1)Usese

What is the purpose of the alt attribute? Why is it important?What is the purpose of the alt attribute? Why is it important?May 11, 2025 am 12:01 AM

The alt attribute is an important part of the tag in HTML and is used to provide alternative text for images. 1. When the image cannot be loaded, the text in the alt attribute will be displayed to improve the user experience. 2. Screen readers use the alt attribute to help visually impaired users understand the content of the picture. 3. Search engines index text in the alt attribute to improve the SEO ranking of web pages.

HTML, CSS, and JavaScript: Examples and Practical ApplicationsHTML, CSS, and JavaScript: Examples and Practical ApplicationsMay 09, 2025 am 12:01 AM

The roles of HTML, CSS and JavaScript in web development are: 1. HTML is used to build web page structure; 2. CSS is used to beautify the appearance of web pages; 3. JavaScript is used to achieve dynamic interaction. Through tags, styles and scripts, these three together build the core functions of modern web pages.

How do you set the lang attribute on the  tag? Why is this important?How do you set the lang attribute on the tag? Why is this important?May 08, 2025 am 12:03 AM

Setting the lang attributes of a tag is a key step in optimizing web accessibility and SEO. 1) Set the lang attribute in the tag, such as. 2) In multilingual content, set lang attributes for different language parts, such as. 3) Use language codes that comply with ISO639-1 standards, such as "en", "fr", "zh", etc. Correctly setting the lang attribute can improve the accessibility of web pages and search engine rankings.

What is the purpose of HTML attributes?What is the purpose of HTML attributes?May 07, 2025 am 12:01 AM

HTMLattributesareessentialforenhancingwebelements'functionalityandappearance.Theyaddinformationtodefinebehavior,appearance,andinteraction,makingwebsitesinteractive,responsive,andvisuallyappealing.Attributeslikesrc,href,class,type,anddisabledtransform

How do you create a list in HTML?How do you create a list in HTML?May 06, 2025 am 12:01 AM

TocreatealistinHTML,useforunorderedlistsandfororderedlists:1)Forunorderedlists,wrapitemsinanduseforeachitem,renderingasabulletedlist.2)Fororderedlists,useandfornumberedlists,customizablewiththetypeattributefordifferentnumberingstyles.

HTML in Action: Examples of Website StructureHTML in Action: Examples of Website StructureMay 05, 2025 am 12:03 AM

HTML is used to build websites with clear structure. 1) Use tags such as, and define the website structure. 2) Examples show the structure of blogs and e-commerce websites. 3) Avoid common mistakes such as incorrect label nesting. 4) Optimize performance by reducing HTTP requests and using semantic tags.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)