1.利用 CSS 的伪类中的content属性获取attr中的信息

效果图:鼠标放上去出现提示

css代码:

.box{position:relative;display:inline-block;margin:100px;}
.box:hover:after{content: attr(data-msg);position:absolute;top:100%;left:0;display:inline-block;background:rgba(0,0,0,0.8);color:#fff;border-radius:5px;line-height:25px;padding:0 10px;}
.box:hover:before{content:'';border:3px solid transparent;border-bottom-color:rgba(0,0,0,0.8);display:block;position:absolute;top:100%;margin-top:-6px;left:50%;tansform:translateX(-50%);}

html代码:

<div class="box" data-msg="hahaha">43343</div>

 

2.实现带边框的三角形,利用伪类实现

  比如弹框中的这种效果:

  css代码:

    .triangle{
            position:relative;
            width:0px;
            height:0px;
            border: 11px solid transparent;
            border-top: 10px solid #ddd;
            border-bottom-width:0px;
        }
        .triangle:after{
                content: '';
                position: absolute;
                display: block;
                z-index: 4;
                left: -10px;
                top: -10px;
                width: 0;
                height: 0;
                border: 10px solid transparent;
                border-top: 10px solid #fdf8f8;
                border-bottom: 0;
        }

  html代码  

<div class="triangle"></div>