css - 断续边界+边界半径

Question

通过css做这样的边框是真的吗？


我想过

border: 3px solid white;
border-top: none;

和带渐变的伪元素，但不完全一样。

Answer 1

您可以通过添加带有渐变的伪元素来实现。透明 -> 白色 -> 透明。

FIDDLE

CSS

div
{
    width: 600px;
    height: 200px;
    border: 5px solid black;
    border-radius: 20px;
    position: relative;
    margin: 50px;
}
div:before
{
    content: '';
    position: absolute;
    top:-5px;
    left:0;right:0;
    margin:auto;
    height: 5px;
    width: 80%;

    background: -moz-linear-gradient(left,  rgba(255,255,255,0) 0%, rgba(255,255,255,0) 1%, rgba(255,255,255,1) 17%, rgba(255,255,255,1) 85%, rgba(255,255,255,0) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, right top, color-stop(0%,rgba(255,255,255,0)), color-stop(1%,rgba(255,255,255,0)), color-stop(17%,rgba(255,255,255,1)), color-stop(85%,rgba(255,255,255,1)), color-stop(100%,rgba(255,255,255,0))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(left,  rgba(255,255,255,0) 0%,rgba(255,255,255,0) 1%,rgba(255,255,255,1) 17%,rgba(255,255,255,1) 85%,rgba(255,255,255,0) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(left,  rgba(255,255,255,0) 0%,rgba(255,255,255,0) 1%,rgba(255,255,255,1) 17%,rgba(255,255,255,1) 85%,rgba(255,255,255,0) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(left,  rgba(255,255,255,0) 0%,rgba(255,255,255,0) 1%,rgba(255,255,255,1) 17%,rgba(255,255,255,1) 85%,rgba(255,255,255,0) 100%); /* IE10+ */
background: linear-gradient(to right,  rgba(255,255,255,0) 0%,rgba(255,255,255,0) 1%,rgba(255,255,255,1) 17%,rgba(255,255,255,1) 85%,rgba(255,255,255,0) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#00ffffff', endColorstr='#00ffffff',GradientType=1 ); /* IE6-9 */

}