What is the HTML5 Document Type Declaration and Character Encoding?
Jul 08, 2025 am 01:50 AM
HTML5 document type declaration and character encoding are the basis of web page development, which directly affects page display and parsing. 1. HTML5 uses a concise to declare the document type, which must be located at the top of the file, otherwise the browser may enter "weird mode". 2. It is recommended to use UTF-8 character encoding and use <meta charset="UTF-8"> to avoid garbled problems and ensure multilingual support. 3. In actual development, the complete HTML5 structure should include lang attributes, introduce meta encoding as soon as possible, optional viewport settings, and DOCTYPE must be located in the first row.
HTML5 document type declaration and character encoding are two basic but critical parts in web development. Although they look simple, they directly affect the display effect of the page and the browser's parsing method.
1. HTML5 Document Type Declaration (DOCTYPE)
In HTML5, the document type declaration is very concise, just one sentence:
<!DOCTYPE html>
The purpose of this line of code is to tell the browser that the current document is using the HTML5 standard. It must be written at the top of the HTML file and cannot have anything in front of it (including spaces or comments).
DOCTYPE in previous HTML versions (such as HTML4 or XHTML) is much more complex, for example:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
But now HTML5 simplifies this process, just a simple <!DOCTYPE html> is needed.
Not adding DOCTYPE may cause the browser to enter "weird mode", which will affect page rendering.
2. Character Encoding
HTML5 recommends using UTF-8 as the default character encoding. The way to set character encoding is to add the following meta tags to the <head> section:
<meta charset="UTF-8">
UTF-8 can support almost all language characters, including Chinese, Japanese, Korean, Latin letters, etc., to avoid garbled code problems.
If you forget to set character encoding, or set it incorrectly, the following phenomena may occur:
- The Chinese language on the page becomes a question mark or a garbled code
- An exception occurred in the form submission
- The browser automatically guesses that the encoding causes inconsistent display
It is recommended to always use UTF-8 and make sure that the server is also configured to send UTF-8-encoded response headers.
3. Common practices in practical applications
A complete HTML5 basic structure is usually as follows:
<!DOCTYPE html>
<head>
<meta charset="UTF-8">
Page Title
This is the content of the page.
Pay attention to a few details:
-
<!DOCTYPE html>must be placed in the first line - The
<html>tag should be added withlangattribute to help search engines identify language -
<meta charset="UTF-8">appear in<head>as early as possible
Some developers will add some extra meta information, such as viewport for mobile adaptation:
<meta name="viewport" content="width=device-width, initial-scale=1.0">
These are not necessary, but are very common in modern web development.
Basically that's it. These two settings may seem simple, but if not paid attention, it can easily lead to compatibility or display issues.
The above is the detailed content of What is the HTML5 Document Type Declaration and Character Encoding?. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undress AI Tool
Undress images for free
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
What is Microdata? HTML5 Explained
Jun 10, 2025 am 12:09 AM
MicrodataenhancesSEOandcontentdisplayinsearchresultsbyembeddingstructureddataintoHTML.1)Useitemscope,itemtype,anditempropattributestoaddsemanticmeaning.2)ApplyMicrodatatokeycontentlikebooksorproductsforrichsnippets.3)BalanceusagetoavoidclutteringHTML
Microdata in HTML5: The Key to Better Search Engine Ranking
Jun 12, 2025 am 10:22 AM
MicrodatasignificantlyimprovesSEObyenhancingsearchengineunderstandingandrankingofwebpages.1)ItaddssemanticmeaningtoHTML,aidingbetterindexing.2)Itenablesrichsnippets,increasingclick-throughrates.3)UsecorrectSchema.orgvocabularyandkeepitupdated.4)Valid
Audio and Video : What about browser compatibility?
Jun 11, 2025 am 12:01 AM
Browser compatibility can ensure that audio and video content works properly in different browsers by using multiple formats and fallback strategies. 1. Use HTML5 audio and video tags and provide multiple format sources such as MP4 and OGG. 2. Consider automatic playback and mute strategies and follow the browser's policies. 3. Handle cross-domain resource sharing (CORS) issues. 4. Optimize performance and use adaptive bit rate streaming media technologies such as HLS.
Audio and Video: HTML5 VS Youtube Embedding
Jun 19, 2025 am 12:51 AM
HTML5isbetterforcontrolandcustomization,whileYouTubeisbetterforeaseandperformance.1)HTML5allowsfortailoreduserexperiencesbutrequiresmanagingcodecsandcompatibility.2)YouTubeofferssimpleembeddingwithoptimizedperformancebutlimitscontroloverappearanceand
Audio and Video: can i record it?
Jun 14, 2025 am 12:15 AM
Yes,youcanrecordaudioandvideo.Here'show:1)Foraudio,useasoundcheckscripttofindthequietestspotandtestlevels.2)Forvideo,useOpenCVtomonitorbrightnessandadjustlighting.3)Torecordbothsimultaneously,usethreadinginPythonforsynchronization,oroptforuser-friend
Adding Audio and Video to HTML: Best Practices and Examples
Jun 13, 2025 am 12:01 AM
Use and elements to add audio and video to HTML. 1) Use elements to embed audio, make sure to include controls attributes and alternate text. 2) Use elements to embed video, set width and height attributes, and provide multiple video sources to ensure compatibility. 3) Add subtitles to improve accessibility. 4) Optimize performance through adaptive bit rate streaming and delayed loading. 5) Avoid automatic playback unless muted, ensuring user control and a clear interface.
What is the purpose of the input type='range'?
Jun 23, 2025 am 12:17 AM
inputtype="range" is used to create a slider control, allowing the user to select a value from a predefined range. 1. It is mainly suitable for scenes where values ??need to be selected intuitively, such as adjusting volume, brightness or scoring systems; 2. The basic structure includes min, max and step attributes, which set the minimum value, maximum value and step size respectively; 3. This value can be obtained and used in real time through JavaScript to improve the interactive experience; 4. It is recommended to display the current value and pay attention to accessibility and browser compatibility issues when using it.
How can you animate an SVG with CSS?
Jun 30, 2025 am 02:06 AM
AnimatingSVGwithCSSispossibleusingkeyframesforbasicanimationsandtransitionsforinteractiveeffects.1.Use@keyframestodefineanimationstagesforpropertieslikescale,opacity,andcolor.2.ApplytheanimationtoSVGelementssuchas,,orviaCSSclasses.3.Forhoverorstate-b
