Elementary Introduction to HTML basic grammar

Source: Internet
Author: User


What is HTML?

HTML is a language used to describe a Web page.
HTML refers to Hypertext Markup Language (Hyper Text Markup Language)
HTML is not a programming language, but a markup language (markup language)
Markup language is a set of tag tags (markup tag)
HTML uses tag tags to describe web pages


HTML tags

HTML tag tags are often referred to as HTML tags (html tag).
HTML tags are keywords surrounded by angle brackets, such as HTML tags are usually paired up, such as <b> and </b>
The first label in the pair is the start tag, the second is the end tag
Start and end tags are also known as open tags and closed labels


HTML document = Web page
HTML Document Description Web page
HTML documents contain HTML tags and plain text
HTML documents are also called Web pages


The HTML title is defined by tags such as The HTML paragraph is defined by the <p> tag.
HTML links are defined by the <a> tag.
HTML images are defined by tags.
HTML tables are defined by the <table> tag.
HTML annotations are defined by <!--> tags.

HTML documents are defined by HTML elements.
The HTML element refers to all the code from the start tag (start tag) to the end tag (end tag).

HTML elements that have no content are called empty elements. The empty element is closed in the Start tab.
<br/> is the empty element without closing the label (the <br/> tag defines a newline).
In XHTML, XML, and future versions of HTML, all elements must be closed.
Adding slashes to the start tag, such as <br/>, is the correct way to close an empty element, which is accepted by HTML, XHTML, and XML.

Property provides additional information for HTML elements.
<H1 align= "Center" > has additional information about alignment.
<body bgcolor= "Yellow" > has additional information about the background color.
<table border= "1" > has additional information about the table border.
Property values should always be included in quotation marks. Double quotes are the most common, but there is no problem with single quotes.
In some cases, such as the attribute value itself contains double quotes, you must use single quotation marks.

<HR/> Tags Create horizontal lines in the HTML page.
The HR element can be used to split the content.

Note: The opening parenthesis (the left parenthesis) needs to be immediately followed by an exclamation mark, which is not required until the closing parenthesis (the right parenthesis).

If you want to wrap (a new line) without creating a new paragraph, use the <br/> label. The <br/> element is an empty HTML element. Because the close tag doesn't make any sense, it doesn't have an end tag.

The syntax for defining an image is: url refers to the location where the image is stored. If the image named "Boat.gif" is in the images directory of www.w3school.com.cn, its URL is http://www.w3school.com.cn/images/boat.gif.
The ALT attribute is used to define a string of prepared, replaceable text for an image. The value of the replacement Text property is user-defined.

The table is defined by the <table> tag. The table header is defined using the <th> tag. Each table has several rows (defined by the <tr> tag) and each row is split into several cells (defined by the <td> tag). The letter TD refers to the table data, which is the contents of the data cell. Data cells can contain text, pictures, lists, paragraphs, forms, horizontal lines, tables, and so on.

The unordered list starts with the <ul> tag. Each list item starts at <li>. The sequence list starts with the <ol> tag. Each list item starts with the <li> label. The custom list starts with the <dl> tag. Each custom list item starts with <dt>. The definition of each custom list item starts with <dd>.

Block-level elements usually start (and end) with a new line when the browser is displayed. Example: Inline elements typically do not start with new lines when they are displayed. Example: <b>, <td>, <a>,

The <div> element has no specific meaning. In addition, because it belongs to a block-level element, the browser displays the folded line before and after it. Another common use of the <div> element is the document layout. It replaces the old-fashioned way of using tables to define layouts. Using the <table> element for document layout is not the correct use of the table. The function of the <table> element is to display tabular data.

A form is a region that contains form elements. The form is defined using the form label (<form>).

<form name= "Input" action= "html_form_action.asp" method= "Get" >
Username:
<input type= "text" name= "user"/>
<input type= "Submit" value= "Submit"/>
</form>
If you type a few letters in the text box above and click the Confirm button, the input data will be transferred to the "html_form_action.asp" page. The page will display the results of the input.

The frame tag defines the HTML document that is placed in each frame. If a frame has a visible border, the user can drag the border to change its size. To prevent this from happening, you can add: noresize= "Noresize" to the <frame> tag.
Add <noframes> tags to browsers that do not support frames.

You cannot use <body></body> tags with <frameset></frameset> tags simultaneously! However, if you add a <noframes> tag that contains a piece of text, you must nest the text in the <body></body> tag. (in the first instance below, you can see how it is implemented.) )

An IFRAME is used to display Web pages within a Web page. The height and Width properties are used to specify the heights and widths of the IFRAME. The Frameborder property specifies whether the border around the IFrame is displayed. <iframe src= "demo_iframe.htm" frameborder= "0" ></ifrrame>

Focus on the framework and layout

Elementary Introduction to HTML basic grammar

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