1. Inclusion selector
The two parts before and after the inclusion selector are separated by spaces, based on the ancestor element specified by the left selector, and then search under this element When defining a selector that matches the lower-level element
that matches the selector on the right, you must ensure that the first object in the HTML structure can contain the second object.
2. Simple example
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>包含</title><style type="text/css">/*定义类样式*/.div1{ font-size:14px; color:#FF0000; }/*定义类样式下的标题元素*/.div1 h1{ color:#FF00FF; }/*定义类样式下的span元素*/.div1 span{ color:#0000FF;}</style></head><body><div class="div1">这是类 <h1 id="这是个标题-span-这是标题中的SPAN元素-span">这是个标题<span>这是标题中的SPAN元素</span></h1></div></body></html>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>包含</title><style type="text/css">/*定义类样式*/.div1{ font-size:14px; color:#FF0000; }/*定义类样式下的标题元素*/.div1 h1{ color:#FF00FF; }/*定义类样式下的span元素*/.div1 span{ color:#0000FF;}</style></head><body><div class="div1">这是类 <h1 id="这是个标题-span-这是标题中的SPAN元素-span">这是个标题<span>这是标题中的SPAN元素</span></h1></div></body></html> Result:
Give an example of an HTML tag with an attribute.May 16, 2025 am 12:02 AMThe usage methods of HTML tags and attributes include: 1. Basic usage: Use tags such as and, and add necessary information through attributes such as src and href. 2. Advanced usage: Use data-* custom attributes to achieve complex interactions. 3. Avoid common mistakes: Make sure the property values are surrounded by quotes. 4. Performance optimization: Keep it simple, use standard attributes and CSS class names to ensure that the image has alt attributes. Mastering these will improve web development skills.
What is the difference between an HTML tag and an HTML attribute?May 14, 2025 am 12:01 AMHTMLtagsdefinethestructureofawebpage,whileattributesaddfunctionalityanddetails.1)Tagslike,,andoutlinethecontent'splacement.2)Attributessuchassrc,class,andstyleenhancetagsbyspecifyingimagesources,styling,andmore,improvingfunctionalityandappearance.
The Future of HTML: Evolution and TrendsMay 13, 2025 am 12:01 AMThe 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?May 12, 2025 am 12:01 AMHTMLattributesarecrucialinwebdevelopmentforcontrollingbehavior,appearance,andfunctionality.Theyenhanceinteractivity,accessibility,andSEO.Forexample,thesrcattributeintagsimpactsSEO,whileonclickintagsaddsinteractivity.Touseattributeseffectively:1)Usese
What is the purpose of the alt attribute? Why is it important?May 11, 2025 am 12:01 AMThe 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 ApplicationsMay 09, 2025 am 12:01 AMThe 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?May 08, 2025 am 12:03 AMSetting 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?May 07, 2025 am 12:01 AMHTMLattributesareessentialforenhancingwebelements'functionalityandappearance.Theyaddinformationtodefinebehavior,appearance,andinteraction,makingwebsitesinteractive,responsive,andvisuallyappealing.Attributeslikesrc,href,class,type,anddisabledtransform
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