今天小编跟大家讲解下有关纯css实现输入框placeholder动效及输入校验 ，相信小伙伴们对这个话题应该有所关注吧，小编也收集到了有关纯css实现输入框placeholder动效及输入校验 的相关资料，希望小伙伴们看了有所帮助。
背景话不多说，我们能否用纯css实现以下效果:
答案是肯定的。
借助css:placeholder-shown :valid :invalid伪类及html5 input pattern 属性就可以实现，:placeholder-shown伪类目前兼容性如下：
直接上代码！
html:<!DOCTYPE html><html><head> <meta charset="utf-8"> <meta name="viewport"content="width=device-width"> <title>js Bin</title></head><body> <div class="input-fill-box"> <input class="input-fill"placeholder="邮箱"pattern="^[A-Za-z0-9\u4e00-\u9fa5]+@[a-zA-Z0-9_-]+(\.[a-zA-Z0-9_-]+)+$"required> <a href=""class="clear">close</a> <label class="input-label">邮箱</label></div></body></html>css:.input-fill{ width: 100%; margin: 0; font-size: 16px; line-height: 1.5; outline: none; padding: 20px 16px 6px; border: 1px solid transparent; background: #f5f5fa; border-radius:10px; transition: border-color .25s;}.input-fill:placeholder-shown::placeholder { color: transparent; }.input-fill-box { width: 50%; position: relative;}.input-label { position: absolute; left: 16px; top: 14px; pointer-events: none; color:#BEC1D9; padding: 0 2px; transform-origin: 0 0; pointer-events: none; transition: all .25s;}.input-fill:not(:placeholder-shown) ~ .input-label,.input-fill:focus ~ .input-label { transform: scale(0.75) translate(0px, -14px); }.input-fill:focus{ border: 2px solid #1d31aa;}.clear{ position:absolute; top:10px; right:-20px; display: none; transition: all .25s;}.input-fill::-ms-clear { display: none; }.input-fill:not(:placeholder-shown) + .clear { display: inline; }.input-fill:valid { border-color: green; box-shadow: inset 5px 0 0 green;}.input-fill:not(:placeholder-shown):invalid { border-color: red; box-shadow: inset 5px 0 0 red;}更多精彩内容请关注https://github.com/abc-club/
来自：https://segmentfault.com/a/1190000020252161
来源：爱蒂网
