1px ios 安卓

粗暴版

js
    <script>
        if (/iP(hone|od|ad)/.test(navigator.userAgent)) {
            var v = (navigator.appVersion).match(/OS (\d+)_(\d+)_?(\d+)?/),
                version = parseInt(v[1], 10);
            if(version >= 8){
                document.documentElement.classList.add('hairlines')
            }
        }
    </script>

css 
/*1px hack*/
.hairlines * {
    border-width: 0.5px !important;
}

或者用伪类

            &::before {
                content: "";
                 position: absolute;
                 left: 0;
                 width: 200%;
                 height: 0;
                border-bottom: 1px solid #dedede;
                transform-origin: left top;
                transform: scale3d(0,0.5,0.5);
                -webkit-transform: scale3d(0.5,0.5,0.5); /* Chrome, Safari, Opera */
                -ms-transform: scale3d(0,0.5,0.5); /* IE 9 */
            }