JavaScript Change the Border Width of Div

To change the border width of a div using JavaScript, get reference to the element, and assign required width value to the element.style.borderWidth property.

Example

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
</head> 
<body>
    <h2>Change Border Width of Div in JavaScript</h2>
    <div id="myDiv" style="border:2px solid green">
        <p>This is a paragraph in Div.</p>
        <span>This is a span in Div.</span>
    </div>
    <br>
    <button type="button" onclick="changeStyle()">Click Me</button>
    <script>
    function changeStyle(){
        var element = document.getElementById("myDiv");
        element.style.borderWidth = "5px";
    }
    </script>
</body>
</html>

Conclusion

In this JavaScript Tutorial, we learned how to change the border width of a div using JavaScript.