/*fixed定位:相对于浏览器窗口*/
position: fixed;<html>
<head><meta charset="utf-8"><title>绝对定位、相对定位</title><style> #d{ width: 200px; height: 200px; background: red; } #d1{ width: 50px; height: 50px; background: yellow; /*相对定位:相对于元素本身应该在的位置移动*/ position: relative; left: 20px; bottom: 20px; } #d2{ width: 50px; height: 50px; background: pink; } #dd{ width: 200px; height: 200px; background: blue; position: relative; } #dd1{ width: 50px; height: 50px; background: orange; left: 20px; bottom: 20px; /*绝对定位:距离父类(有position样式的父类)...body*/ position: absolute; left: 20px;top: 50px; z-index: 100; } #dd2{ width: 50px; height: 50px; background: grey; position: absolute; left: 30px; top: 60px; z-index: 50; }</style></head><body>
<div id="d"> <div id="d1"></div> sadassafasf <div id="d2"></div></div><div id="dd"> <div id="dd1"></div> <div id="dd2"></div></div></body></html>
<html>
<head><meta charset="utf-8"><title>无标题文档</title><style> #d{ width: 200px; height: 200px; background: red; /*fixed定位:相对于浏览器窗口*/ position: fixed; left: 20px; top: 50px; }</style></head><body>
<div id="d"></div><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br></body></html>