HTML5 Study Notes: Three HTML elements, attributes, titles, paragraphs, and html5 Study Notes
I. HTML elements
An HTML document consists of Nested HTML elements.
<! Doctype html> <body> <p> This is the first paragraph </p> </body> Do not forget the end tagEven if you forget to use the end tag, most browsers correctly display HTML.
Empty HTML ElementHTML elements without content are called empty elements. Empty elements are disabled in the start tag.
<Br> is an empty element that does not close the tag (<br> label definition line feed ).
In XHTML, XML, and HTML of future versions, all elements must be disabled.
Adding a slash to the start tag, such as <br/>, is the correct method to disable empty elements. HTML, XHTML, and XML both accept this method.
Even if <br> is valid in all browsers, using <br/> is actually a long-term guarantee.
HTML prompt: use lower-case tagsHTML tags are not case sensitive: <P> equivalent to <p>. Many websites use uppercase HTML tags.
W3CSchool uses lower-case tags because the W3C is in HTML 4.RecommendationUse lower-case letters, and in future (X) HTML versionsForceUse lower-case letters.
Ii. HTML attributes
Attribute values should always be enclosed in quotation marks.
Double quotation marks are the most commonly used, but it is no problem to use single quotation marks.
Tip:In some cases, for example, if the attribute value itself contains double quotation marks, you must use single quotation marks. For example, name = 'John "AB" Nelson'
HTML prompt: use lower-case attributesAttributes and attribute values are not case sensitive.
However, the World Wide Web Alliance recommends lower-case attributes/attribute values in its HTML 4 Recommendation Standard.
The new version (X) HTML requires lower-case attributes.
Applicable to attributes of most HTML elements:
Iii. HTML titleHeading is defined using the
<H1> define the largest title. <H6> define the smallest title.
H1 should be used as the title (the most important), followed by h2 (the second important), followed by h3, and so on.
HTML horizontal line<Hr> Create a horizontal line for the tag on the HTML page.
The hr element can be used to separate content.
HTML commentYou can insert comments into HTML code to improve readability and make the code easier to understand. The browser ignores and does not display comments.
Note:An exclamation mark must be followed after the parentheses begin (the left parenthesis), but not before the parentheses end (the right Parenthesis.
Common labels:
The sum code above is as follows:
<! Doctype html> <H1> title:
Iv. HTML SectionThe section is defined by the <p> label.
HTML line breaksIf you want to wrap a line (New Line) without generating a new paragraph, use the <br/> label:
Example:
<! Doctype html> <body>:
The labels used above:
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