To set all the border-radius properties in JavaScript, use the borderRadius property. Set the border-radius properties at once using this.
Example
You can try to run the following code to learn how to set all the four border-radius properties −
<!DOCTYPE html> <html> <head> <style> #box { border: thick solid gray; width: 200px; height: 200px } </style> </head> <body> <div id="box">Demo Text</div> <br><br> <button type="button" onclick="display()">Add border radius</button> <script> function display() { document.getElementById("box").style.borderRadius = "20px"; } </script> </body> </html>