Compatible with unknown height div vertical centering effect of various browsers_html/css

Compatible with unknown height div vertical centering effect of various browsers_html/css_WEB-ITnose

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Release： 2016-06-24 11:41:22

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Compatible with the vertical centering effect of divs of unknown height in various browsers:
Centering a div vertically in its parent object is not as simple as centering the div horizontally in the parent element. Just simply set margin:0px auto for this element. Although you can vertically center the div with the parent element using some attributes, it is not compatible with some browsers. Here is a method that is compatible with all major browsers. browser way.
Let’s look at a code example first:

<!DOCTYPE html><html><head><meta charset="utf-8"><meta name="author" content="http://www.51texiao.cn/" /><title>蚂蚁部落</title> <style type="text/css"> .parent {   width:200px;   height:200px;   background-color:green;   display:table-cell;   vertical-align:middle; } .children {   background-color:red;   width:80px;   text-align:center;   margin:0px auto; } </style> </head> <body> <div class="parent">   <div class="children">蚂蚁部落</div> </div> </body> </html>

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The above code runs normally in standard browsers and can vertically center align child elements in the parent element, but IE6 and IE7 is not so powerful, so the code needs to be modified to be compatible with IE6 and IE7 browsers. However, if you just add CSS compatible code without making structural changes, it will be difficult to achieve compatibility with IE6 and IE7. Here is the above code Adjust as follows:

<!DOCTYPE html><html><head><meta charset="utf-8"><meta name="author" content="http://www.51texiao.cn/" /><title>蚂蚁部落</title> <style type="text/css"> .parent {   width:200px;   height:200px;   background-color:green;   position:relative;   display:table; } .middle {   display:table-cell;   vertical-align:middle;   *position:absolute;   *top:50%;   *left:50%; } .children {   background-color:red;   width:80px;   text-align:center;   margin:0px auto;   *position:relative;   *top:-50%;   *left:-50%; } </style> </head> <body> <div class="parent"> <div class="middle">    <div class="children">蚂蚁部落</div> </div> </div> </body> </html>

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The above code achieves the effect of vertically centering the div. You do not need to regard this piece of code as a modified version of the first piece of code, but as a completely new version. Here is a brief introduction to how the next code achieves this effect:
1. Implementation ideas:
Since IE6 and IE7 do not support display:table-cell and display:table, the height of the middle object is the same as the height of the children object. Of course, if the width of the children object is not set, their sizes are exactly the same. Use absolute positioning for the middle object in IE6 and IE7, and the reference object is the parent object, and set its top value to 50%, so that the upper edge of the middle object is exactly in the middle of the vertical position of the parent object. Also use positioning for the children object, and then set its top value to -50%, so that it moves up by half the height of the middle, so that the center of the children object is located in the middle of the vertical direction of the parent object. This achieves the vertical centering effect of the children object. Some friends here may ask why other standard browsers do not use this method. This is because if the height of the middle object is not set, the set top attribute will not take effect. The following pictures are the renderings of running under IE6 and IE7 after setting the middle background color to blue:

2. Explanation of knowledge points:
1. The asterisk (*) is In order to be compatible with IE6 and IE7 browsers.
2. Display:table should be added to the parent object corresponding to the display:table-cell in the middle object. Otherwise, the size and content of the middle element will be adaptive instead of the same size as the parent element, so it will not be possible to implement Standard browsers center the children object vertically.

The original address is: http://www.51texiao.cn/div_cssjiaocheng/2015/0501/503.html