Correction status:Uncorrected
Teacher's comments:
今天的课程:css中常用定位;伪类选择器hover;元素显示隐藏
定位:
relative:相对定位元素的定位是相对其正常位置,相对定位元素经常被用来作为绝对定位元素的容器块;
fixed:元素的位置相对于浏览器窗口是固定位置;
absolute:
绝对定位的元素的位置相对于最近的已定位父元素,如果元素没有已定位的父元素,那么它的位置相对于出始包含块
特点:绝对定位使元素的位置与文档流无关,因此不占据空间 ; 通常与相对定位连用(子绝父相)
z-index 属性设置元素的堆叠顺序 注意:Z-index 仅能在定位元素上奏效
伪选择器:hover
鼠标悬浮到元素上会触发hover
元素显示与隐藏:
display:block / none
优酷案例
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <link rel="stylesheet" href="static/font-awesome-4.7.0/css/font-awesome.min.css"> <style type="text/css"> *{margin: 0;padding: 0} li{list-style: none;float: left} a{text-decoration: none;color: #000;} .clear{clear: both} /**/ .mr{margin-right: 10px;} .l{float: left} /* 左浮动 */ a span{margin-top: 5px} li small{margin-top: 2px;} .conts{ width: 1740px; margin: 0 auto; } .cont{width: 100%; margin-top: 20px; } .cont-ul{line-height: 70px;} .hot-tv img{width: 240px;height: 360px;} .tab li{margin-right: 20px;} .tv-tab img{width: 240px;height: 135px;} .tv-tab img:hover{box-shadow: 0px 2px 20px skyblue} .tv-show .tv-tab{margin-bottom: 15px;} /*头部*/ .header{ position: relative; width: 100%; height: 520px; background: #E8E8E8; } .pic-show{ width: 1740px; height: 520px; margin: 0 auto; background: url("https://ykimg.alicdn.com/develop/image/2019-03-14/4be9792c38ab7f0abee4d12542e09905.jpg") no-repeat; } .bg{background:url("https://gw.alicdn.com/mt/TB1A4OaolTH8KJjy0FiXXcRsXXa-1664-520.png"); width: 100%; height: 100%; position: absolute; top: 0; left: 0; z-index: 10; } .menu_ul{position: fixed; top:20px; left: 120px; z-index: 15; } .menu_ul form{ width: 500px; height: 40px; position: relative; left: 430px; } .menu_ul input{ width: 500px;height: 40px; border-radius: 100px; border: none; background: rgba(234,234,234,0.5); outline: 0; } .menu_ul button{ position: absolute; top:0; right: 0; width: 90px; height: 40px; border-top-right-radius: 30px; border-bottom-right-radius: 30px; background: #B30702; border: none; color: white; outline: 0; } .menu_li{position: relative; } </style> </head> <body> <div class="header"> <div class="pic-show"></div> <div class="bg"></div> <div class="menu_ul"> <div class="l"> <img class="l" src="https://img.alicdn.com/tfs/TB1dw0vqHGYBuNjy0FoXXciBFXa-120-24.png"> <form action="" method="" class="l"> <input type="text" name=""> <button>全网搜</button> </form> </div> <ul class="menu_li"> <li><i class="fa fa-diamond"></i></li> </ul> </div> </div> <div class="conts"> <div class="cont"> <div class="cont-ul"> <h2>正在热播</h2> </div> <ul class="hot-tv"> <li class="mr"> <a href=""> <img src="http://r1.ykimg.com/050E00005C774CC7859B5D335803D155?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://r1.ykimg.com/050E00005C346D1C859B5E79630A6226?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://r1.ykimg.com/050E00005C346D1C859B5E79630A6226?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://r1.ykimg.com/050E00005C346D1C859B5E79630A6226?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://r1.ykimg.com/050E00005C346D1C859B5E79630A6226?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://r1.ykimg.com/050E00005C346D1C859B5E79630A6226?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li > <a href=""> <img src="http://r1.ykimg.com/050E00005C346D1C859B5E79630A6226?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> </ul> <div class="clear"></div> </div> <div class="cont"> <div class="cont-ul"> <h2 class="l mr">聚集 ></h2> <ul class="tab l"> <li><a href="">最新</a></li> <li><a href="">大陆</a></li> <li><a href="">日韩</a></li> <li><a href="">热播</a></li> </ul> <div class="clear"></div> </div> <div class="tv-show"> <div class="big-show l mr"> <a href=""> <img src="http://ykimg.alicdn.com/develop/image/2019-02-13/ed026566424880372286e5d5bafbf28c.jpg"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </div> <ul class="tv-tab l"> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> </ul> <ul class="tv-tab l"> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li class="mr"> <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> <li > <a href=""> <img src="http://ykpic.alicdn.com/haitun-image/prod/compress/20190103/01ceb88d2d75f7e8fff266316808b974.jpg?x-oss-process=image/resize,w_290/interlace,1/quality,Q_100/sharpen,100"><br> <span>看中国:宁夏</span> </a><br> <small>低调的宁夏 没了四级</small> </li> </ul> </div> </div> </div> </body> </html>
点击 "运行实例" 按钮查看在线实例
总结:
定位绝对定位是和相对定位一起使用的,一些有用的边框与背景样式可以很***。边框圆角与透明度背景