Summary of practical experience of HTML knowledge points

1. The table tag is table, tr is row, td is cell, cellspacing is the distance between cells, cellpadding is the inner margin, caption is the title of the table, colspan is the merged column, rowspan is parallel, and the table tbody
All are default. If you add multiple tdody, you can solve the problem of page display.

2. Hyperlink email link mailto: abc@shouhu.com
3.<input type=”file”> can be used for long transfer
4. Label can set shortcut keys
5.ini is a simple configuration information description, xml is a complex information description

6. Regular expressions are a type of rule used to manipulate strings. They are represented by symbols to simplify string manipulation. Common operations include matches:
Find: pattern, and macther object cutting: split
Replace: replaceAll
Web crawler: reads source files through the network and io, and obtains the meaning of the groups in the regular expression that meet the rules in the web page through the rules: encapsulate some of the rules for reuse. Direction Reference Group

7.html is hypertext markup language, which is composed of tags. Data in html are divided into tags because the data in the division can be operated by changing the attribute value in the tag.
Determine the html code range. <html></html>
In this scope, China can define two parts, one is the head and the other is the body.
Tag features: For data encapsulation, there are start tags and end tags, but some tags only have one function, so there is no need for an end tag. The specification requires that the tag must end, so such tags end internally.

8. Common tags <font></font>.
Title tags <h1><h2><h3>
List tags: <dl></dl> both have parent items: <dt>
Lower level item: <dd>
Bullet tag: <ul> is unsigned
<ol> is a symbol. Both list items have <li> enclosing image tags: <img>
Table tag: <table> is composed of rows, which are composed of cells. There is a default tbody tag in the table to format the table.
Hyperlink tag: <a href=” ” > Sina website target
When clicked, the corresponding resolution program of the engine will be started to find the specified host.
Another function of a hyperlink: positioning mark form tag: this tag can interact with the server.
There are 10 types: text, password, file, checkbox, radio, hidden, button, submit, reset, image
Image has the ability to submit

Drop-down menu:
<select>
<option></option>
</select>
Text area: <textarea> form components usually need to define name and value attributes

9. Form components usually need to define name and value attributes because they need to be sent to the server.

10. The difference between get and post
get: The submitted data will be displayed in the address bar
post: data will not be displayed in the address bar

get: The size of the submitted data will be limited by the address bar
post: can submit large volume data

get: Not safe for sensitive information
post: For sensitive information security

Get: will encapsulate the submission information in the request line, that is, before the HTTP message header
post: will encapsulate the submission information in the data line, that is, after the blank line after the http message header

Components that use forms do not necessarily need to define form tags. Form tags are only used when data needs to be submitted to the server.

11. CSS Cascading Style Sheets separate the styles in the web page, and CSS is completely used to control the reusability and scalability of the enhanced styles. Format: Selector
Four ways to combine CSS and HTML code
1. Each HTML tag uses a style attribute
2. When a page has multiple tags with the same style, they can be reused
3. When there are multiple pages with the same tag style, you can also encapsulate the style into a separate CSS and define it in each page
4. Link in the head tag via HTML

12. Selector:
1. Tag selector
2. Class Selectors
3. id selector

Priority id>class>label extension selector
1Association selector: actually styles the tags in the tags
2 Combination selectors:
3. Pseudo-element selector:

13. The difference between div and span
Div: row-level area
Span: block-level area

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