Get the class name of the first <div> element in the document (if any):
var x = document.getElementsByTagName("DIV")[0].className;
Click the button to display the value of the class attribute of the div element below.
<!DOCTYPE html> <html> <head> <style> .mystyle {// ww w . jav a 2 s . co m width: 300px; height: 100px; background-color: coral; color: white; margin-bottom: 10px; } </style> </head> <body> <div class="mystyle"> I am a DIV element with class="mystyle" </div> <button onclick="myFunction()">Test</button> <p id="demo"></p> <script> function myFunction() { var x = document.getElementsByTagName("DIV")[0].className; document.getElementById("demo").innerHTML = x; } </script> </body> </html>