前言

看到codepen里面有的按钮搞得很炫酷，但其实也不是很难，就学习记录一下

逐渐出现边框

大体上来说就是当鼠标悬浮的时候触发四个transition，用after、before和span的after和before四个伪类做hover出来的边框

<div class="btn btn-2"><span>borderDynamic</span></div>

.btn-2 {color: white;background-color: rgb(0, 153, 255);transition: all 0.3s ease;}.btn-2 span {display: inline-block;width: 100%;height: 100%;}.btn-2::after,.btn-2::before {content: "";position: absolute;top: 0;right: 0;background-color: rgb(2, 2, 155);transition: all 0.3s ease;}.btn-2 span::after,.btn-2 span::before {content: "";position: absolute;bottom: 0;left: 0;background-color: rgb(2, 2, 155);transition: all 0.3s ease;}.btn-2::after,.btn-2 span::after {width: 1px;height: 0;}.btn-2::before,.btn-2 span::before {width: 0;height: 1px;}.btn-2:hover {background-color: transparent;color: rgb(22, 102, 85);}.btn-2:hover::after,.btn-2 span:hover::after {height: 100%;}.btn-2:hover::before,.btn-2 span:hover::before {width: 100%;}

图形变化

原理和上面类似，都是用伪类去实现

    .btn-3 {background-color: rgb(255, 192, 203);}.btn-3::before {content: "";position: absolute;top: 10%;left: 50%;width: 4%;height: 80%;border-radius: 50%;transform: rotate(45deg);background-color: black;transition: all 0.3s ease;}.btn-3::after {content: "";position: absolute;top: 10%;left: 50%;width: 4%;height: 80%;border-radius: 50%;transform: rotate(-45deg);background-color: black;transition: all 0.3s ease;}.btn-3:hover::before {transform: translateX(-100%) scaleY(80%);}.btn-3:hover::after {transform: translateX(100%) scaleY(80%);}

hover展开的btn

<div class="roundBtn btn-4"><span class="arrow"></span><div class="icon"></div><span class="text">hover</span></div>

/* 圆形动画button */.roundBtn {margin: 10px;width: 50px;height: 50px;border-radius: 25px;background-color: rgb(160, 243, 171);position: relative;transition: all 0.3s ease;}.icon {position: absolute;top: 23px;left: 30px;width: 0px;height: 4px;border-radius: 2px;background-color: black;transform: scale(80%);transition: all 0.3s ease;}.arrow::before {content: "";position: absolute;top: 10px;left: 23px;height: 20px;width: 4px;border-radius: 2px;background-color: black;transform: rotate(-45deg) scale(80%);transition: all 0.3s ease;}.arrow::after {content: "";position: absolute;bottom: 10px;left: 23px;height: 20px;width: 4px;border-radius: 2px;background-color: black;transform: rotate(45deg) scale(80%);transition: all 0.3s ease;}.roundBtn:hover .icon {width: 20px;}.roundBtn:hover .arrow::before {transform: translateX(20px) rotate(-45deg) scale(80%);}.roundBtn:hover .arrow::after {transform: translateX(20px) rotate(45deg) scale(80%);}.roundBtn .text {display: inline-block;position: absolute;left: 50px;top: 0px;width: 80px;height: 50px;line-height: 50px;text-align: center;}.roundBtn:hover {width: 150px;}