html Important knowledge points you must know about PHP

This time I will bring you the important knowledge points you must know about PHP in html. What are the precautions about PHP in html? Here are practical cases, let’s take a look.

Use frameset, frame and iframe to also realize multi-window

2. Use mapping distance usemap on the picture to realize button jump. ------Episode 8

3. The form must have name and value, because when capturing the packet, you can find that they must be submitted

4.fieldset tag—— >legend, lable

5. You can only use margin-top and margin-left to position the div from the page margin.

6.padding-top, padding-left Position the distance between the element inside the div and the div margin

7. The default hyperlink is link. You can set the properties of hover, and visited

8. Four selector priorities: id selector (#)>class selector (.)>html selector>wildcard selection Selector (*)

9. Parent Child selector , such as #id1 span{}-----> similar to a.clas1{};a.clas2 {}
Also #id1 span span. It doesn’t have to be just one level.
(1) The parent-child selector can have multiple levels (but do not exceed three levels in actual development)
(2) There is a strict hierarchical relationship
(3) The parent-child selector is not limited to any type of selector
.s1 #id span
div #id .s2

10. An element can have both id selector and class selector.
For exampleHehe

11. An element can have at most one id selector, but it can have multiple class selectors.
For examplehaha
Special note: When two class selectors conflict, the latter class selector written in the css file will be used. Subject to

12. We can write a separate copy of the common parts of the selector in a certain css file
such as .s1, .s2, .s3{}

13. Inline elements and block elements
(1) Inline elements only occupy the width that can display their own content, and they will not occupy the entire line
(2) Block elements will occupy no matter how much their content is. The entire line, and will be displayed in new lines
==>>Common inline elements are
==>>Common fast elements are

15.CSS box model: The second part of episode 13 will talk about margin, border, padding

16. Pay attention to the default sides of some elements distance. So be careful to get rid of it. For example, ul

17. Positioning
==> Relative positioning: Reposition relative to the position where the element should be displayed. Although it is out of the
standard flow, the position is not allowed to come out and cannot be occupied
==>Absolute positioning: Position the element closest to the element that has broken away from the standard flow. If
there is no parent element (or there is a parent element, but the parent element has not broken away from the standard flow) ),
is positioned relative to the upper left corner of the body
==>Fixed positioning: always positioned with the upper left corner of the window
==>left top attribute has no effect on static, sattic relies on margin_left and
==>z_index positioned by margin_top is used to set the cascading attributes when the object (div) is displayed. The smaller the z-index, the lower it is

18. The value of height and width for inline elements invalid. Unless converted to float (float) or (display:block)

19. There are two things worth learning from the cute house at the end of episode 20. One is the dynamic background image of the link menu bar,
the other is The input box only displays the lower border, and other borders do not display

I believe you have mastered the method after reading these cases. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

Related reading:

How h5 and c3 can animate the movement of planets in the solar system

How to fix div or css table at the specified location

#How to use read-only and disabled in the form

The above is the detailed content of html Important knowledge points you must know about PHP. For more information, please follow other related articles on the PHP Chinese website!