【代码笔记】Web-CSS-CSS Positioning

一，效果图。

 

 

 

二，代码。

 

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<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title>CSS Positioning</title>
    <style>
    p.pos_fixed {
        position: fixed;
        top: 30px;
        right: 5px;
    }
    
    h2.pos_left {
        position: relative;
        left: -20px;
    }
    
    h2.pos_right {
        position: relative;
        left: 20px;
    }
    
    h2.pos_top {
        position: relative;
        top: -50px;
    }
    
    h2.absolute {
        position: absolute;
        left: 100px;
        top: 150px;
    }
    
    img {
        position: absolute;
        left: 0px;
        top: 0px;
        z-index: -1;
    }
    </style>
</head>

<body>
    <p class="pos_fixed">Some more text</p>
    <p><b>Note:</b> IE7 and IE8 supports the fixed value only if a !DOCTYPE is specified.</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <p>Some text</p>
    <h2>This is a heading with no position</h2>
    <h2 class="pos_left">This heading is moved left according to its normal position</h2>
    <h2 class="pos_right">This heading is moved right according to its normal position</h2>
    <p>Relative positioning moves an element RELATIVE to its original position.</p>
    <p>The style "left:-20px" subtracts 20 pixels from the element's original left position.</p>
    <p>The style "left:20px" adds 20 pixels to the element's original left position.</p>
    <h2>This is a heading with no position</h2>
    <h2 class="pos_top">This heading is moved upwards according to its normal position</h2>
    <p><b>Note:</b> Even if the content of the relatively positioned element is moved, the reserved space for the element is still preserved in the normal flow.</p>
    <h2 class="absolute">This is a heading with an absolute position</h2>
    <p>With absolute positioning, an element can be placed anywhere on a page. The heading below is placed 100px from the left of the page and 150px from the top of the page.</p>
    <h1>This is a heading</h1>
    <img src="w3css.gif" width="100" height="140" />
    <p>因为图像元素设置了 z-index 属性值为 -1, 所以它会显示在文字之后。</p>
</body>

</html>
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参考资料：《菜鸟教程》

posted @ 2019-02-02 09:15  花儿迎风笑  阅读(320)  评论(0)  编辑  收藏  举报