内边距与外边距区别（The difference between inside margin and
outer margin）
Do you really know margin? Do you know what characteristics margin has? Do you know what the vertical margin merge is? What is the difference between margin in block elements and inline elements? When should I u padding instead of margin? Do you know negative margin? Do you know the u of negative margin in real work? What are the bug of margin under the common browr?......
Writing CSS, you can't deal with margin, and we don't know much about the CSS attribute, which is our most commonly ud. In this ca, I intend to write this article, one is a summary of their work, but also a carding of their knowledge.
What is Margin?
The CSS margin property defines the space around the element. By using parate attributes, the upper, right, lower, left outer distance can be t. You can also u a simple outer distance property to change all the external distances simultaneously. -- W3School
Boundary, around the element to generate additional blank areas. "Blank space" usually refers to the ar
ea where other elements cannot appear and the parent element background can be en. CSS authority Guide
I love to u the word "margins" to explain margin (as padding can be called "padding", but I just love to call padding as
"filler" or "blank"), the most basic purpo we can clearly understand that margin is to control the elements around the space interval, to each other apart from the visual angle of purpo.
Characteristics of Margin
Margin is always transparent.
Margin us parate attributes to t the upper, right, lower, and left outer distances. Namely: margin-top, margin-right, margin-bottom, margin-left.
Value types are: from the outside margin-width auto length percentage | |突然累了
It can also u the - distance properties at the same time to change all of the outside top right bottom from margin:: left; (eg: margin:10px 20px 30px 40px) is just above the memory elements clockwi around the "right left" memory.
And the specification also provides the numerical method of ellipsis, basically as follows:七夕节有哪些风俗
1, if margin has only one value, the upper, lower right and left margin are the same value. For example: margin:10px; equal to margin:10px 10px 10px 10px;
2, if margin has only two values, the first value reprents the upper and lower margin values, and the cond value is the value of about margin. For example: margin:10px 20px; equal to
作比较句子margin:10px 20px 10px 20px;
3, if margin has three values, the first value reprents the upper margin value, the cond value reprents the value of the left and right margin, and the third value indicates the value of the lower margin. For example: margin:10px 20px 30px; equal to margin:10px 20px 30px 20px;
胰岛素抵抗的症状
4, if margin has four values, the four values correspond to the four margin values of the right, the left and the left, respectively. For example: margin:10px 20px 30px 40px;
In practical application, individuals do not recommend the u of three margin value, one is easy to be confud, two days after the change is not easy, if margin:10px 20px 30px written a start; days after demand changes for 10px, right 30px, 30px 20px, left, you have to have the margin open margi
n:10px 30px 30px 20px; laborious and thankless, as a start in margin:10px 20px 30px 20px honest; for it, not in order to save two bytes now and let the day again after the development of rising costs.
百香果的作用与功效Vertical outer margin merge problem
Don't be frightened by the noun above. Simply speaking, the outer distance means that when the two vertical outer margins meet, they form an outer margin. The height of the combined outer distance is equal to the larger of the two outer heights of the merging. You can e the W3Shool CSS margin merge to understand this basic knowledge.书名大全
In actual work,
The merger of the vertical spacing margins are common in the first sub element of the margin-top will open the top of the parent element and the parent element of adjacent elements, and only the standard browr (FirfFox, Chrome, Opera, Sarfi) IE problem, but the good performance. For example, you can e the following code (IE show "normal", under the standard browr view "bug"):
摩肩接踵<html xmlns= "/1999/xhtml" >
<head>
<title> vertical margin merge </title>
<style>
.top{width:160px; height:50px; background:#ccf;}
.middle{width:160px; background:#cfc;}
.middle.FirstChild{margin-top:20px;}
</style>
</head>
<body>
<div class= "top" ></div>
<div class= "middle" >
<div class= "firstChild" - I just want to parate the distance from my parent element. </div>
<div class= "condChild" ></div>
</div>
</body>
</html> if you follow the CSS specification, the "good performance" of IE is actually a mistake, becau the hasLayout rendering of IE leads to this "good performance" look. Other standard browrs display a "problematic" look. Well, it's easy to talk about this problem if you've read the merged CSS margins on the top of the W3Shcool. The cau of the problem is according to the specification, a box if there is no filler (padding-top) and the upper frame (border-top), then the box from the top top and the internal document flow in the first sub elements overlap distance.
Besides the white point is: above the first child of the parent element from the margin-top if no valid border or padding. will keep a layer to find their own "leadership" (parent, ancestor). Just give the leadership to t a valid border or padding margin can effective control of this project without leadership to prevent it leapfrog, leave the decree, put their own margin when the leader of the margi
n implementation. The solution for vertical margins with the already explained above, the middle element parent element in the example to add a border-top or
搀怎么读
