<!doctype html>
<html>
<head>
<title>Test the border transparency</title>
<style>
div {
width: 100px;
height: 100px;
border: 15px solid rgba(0,0,255,0.5);
border-radius: 15px;
position: absolute;
left: 50px;
top: 50px;
}
</style>
</head>
<body>
<div></div>
</body>
</html>