css+dom 四角边框
css 四角边框 border-image-source
css 四角边框 background
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.box,.bgBox{
position: relative;
width:100px;
height: 50px;
top: 100px;
margin: 0 auto;
border: 1px solid #5384ff;
display: flex;
align-items: center;
}
.item{
width: 100%;
height: 100%;
/*高,宽*/
border-image-source:radial-gradient(51% 55%, transparent 0, transparent 100%, #1cd8ff 100%);
/*border-image-source:radial-gradient(51% 55%, #00bb00 0, #ff80e1 100%, #1cd8ff 100%);*/
border-image-slice:.5;
border-width: 5px;
border-style: solid;
border-image-outset: 10px 15px;
}
/*设置颜色,宽度,和长度*/
:root{
--borderColor: #e61aff;
--borderWidth:5px;
--borderLength:20px
}
.bgBox{
top: 200px;
border: 1px solid #263805;
}
.bgItem{
width: 100%;
height: 100%;
background: linear-gradient(to left,var(--borderColor),var(--borderColor)) left top no-repeat, linear-gradient(to bottom, var(--borderColor), var(--borderColor)) left top no-repeat, linear-gradient(to left, var(--borderColor), var(--borderColor)) right top no-repeat, linear-gradient(to bottom, var(--borderColor), var(--borderColor)) right top no-repeat, linear-gradient(to left, var(--borderColor), var(--borderColor)) left bottom no-repeat, linear-gradient(to bottom, var(--borderColor), var(--borderColor)) left bottom no-repeat, linear-gradient(to left, var(--borderColor), var(--borderColor)) right bottom no-repeat, linear-gradient(to left, var(--borderColor), var(--borderColor)) right bottom no-repeat;
background-size: var(--borderWidth) var(--borderLength), var(--borderLength) var(--borderWidth), var(--borderWidth) var(--borderLength), var(--borderLength) var(--borderWidth);
/*border: 5px solid transparent;*/
}
</style>
</head>
<body>
<!-- border-image-source-->
<div class="box">
<div class="item"></div>
</div>
<!--background-size-->
<div class="bgBox">
<div class="bgItem"></div>
</div>
</body>
</html>