要在JavaScript中设置元素边框的颜色，请使用borderColor属性。
示例
您可以尝试运行以下代码以了解如何设置元素边框的颜色-
<!DOCTYPE html>
<html>
<head>
<style>
#box {
height: 300px;
width: 200px;
border: thick dashed yellow;
}
</style>
</head>
<body>
<div id="box">
<p>DEMO TEXT</p>
<p>DEMO TEXT</p>
<p>DEMO TEXT</p>
<p>DEMO TEXT</p>
</div>
<br>
<button type="button" onclick="display()">Set new color of border</button>
<script>
function display() {
document.getElementById("box").style.borderColor = "green";
}
</script>
</body>
</html>
