css中伪元素before或after中content的特殊用法attr

html代码如下：

<div class="haorooms">
        <span data-haorooms="haorooms鼠标效果tips-纯css">haorooms测试</span>
</div>

css代码如下：

.haorooms{margin-top:30px}    

span{
            position: relative;
            display: inline-block;
        }
        span:hover{
            cursor: pointer;
        }
        span:hover:before{
            content: attr(data-haorooms);
            background-color: #2085c5;
    border-radius:3px;
            color: #fff;
            padding: 10px;
            position: absolute;
            left: 100%;
            top: -70%;
            margin-left: 8px;
            white-space: pre; 
        }
        span:hover:after{
            content: "";
            position: absolute;
            width: 0;
            height: 0;
            border-right: 8px solid #2085c5;
            border-top: 8px solid transparent;
            border-bottom: 8px solid transparent;
        }

当然，用纯css写tips，

制作半边文字

效果如下：

html代码：

<span class="haorooms" data-content="前">前</span>
<span class="haorooms" data-content="端">端</span>
<span class="haorooms" data-content="博">博</span>
<span class="haorooms" data-content="客">客</span>

css代码：

.haorooms {
    position:relative;
    display:inline-block;
    font-size:80px; /*  任何宽度都可以 */
    color: black; /* 任何颜色，或透明 */
    overflow:hidden;
    white-space: pre; /* 处理空格 */
}
.haorooms:before {
    display:block;
    z-index:1;
    position:absolute;
    top:0;
    left:0;
    width: 50%;
    content: attr(data-content); /* 伪元素的动态获取内容 */
    overflow:hidden;
    color: #f00;
}