Javascript DOM Element class name set
<!DOCTYPE html> <html> <head> <style type="text/css"> .message-style1 { color: navy; font-weight: bold; background-color: gray; }//from www . j a v a 2s. c o m </style> </head> <body> <div id="divMessage"> Here is a message. </div> <input type="button" value="Toggle Style" onclick="toggleStyle()" /> <script type="text/javascript"> function toggleStyle() { let divMessage = document.getElementById("divMessage"); if (divMessage.className === "message-style1") { divMessage.className = ""; } else { divMessage.className = "message-style1"; } } </script> </body> </html>