To set the color of the bottom border in JavaScript, use the borderBottomColor property. It allows you to set the border color for the bottom of a border.
Example
You can try to run the following code to learn how to set the color of the bottom border −
<!DOCTYPE html>
<html>
<head>
<style>
#box {
border: 2px dashed blue;
width: 120px;
height: 120px;
}
</style>
</head>
<body>
<button onclick="display()">Set border bottom color</button>
<div id="box">
<p>Demo Text</p>
<p>Demo Text</p>
</div>
<script>
function display() {
document.getElementById("box").style.borderBottomColor = "yellow";
}
</script>
</body>
</html>