操作方法：点击后活动事件保持活动状态

Question

如何在点击后使此div保持活动状态？

我尝试查找它但看不到任何适用于textarea过渡的内容

CSS：

.comment-box:active {
    /* Settings for Transition */
    height:100px;
    /* Transition: Basic */
    transition-duration:0.8s;
    transition-timing-function:ease;
    /* Transition: Chrome+Safari */
    -webkit-transition-duration:0.8s;
    -webkit-transition-timing-function:ease;
    /* Transition: Mozilla */
    -moz-transition-duration:0.8s;
    -moz-transition-timing-function:ease;
    /* Transition: Opera */
    -o-transition-duration:0.8s;
    -o-transition-timing-function:ease;
}

HTML：

<textarea type="text" validation="required" name="comment" placeholder="type a comment here..." maxlength="500" class="comment-box"></textarea>