document.getElementById("ElementId").className = "";
If you want remove a specific class from the list of classes. just follow the bellow example.
My name is Mukesh Jakhar and I am a Web Application Developer and Software Developer, currently living in Jaipur, India. I have a Master of Computer Application in Computer Science from JNU Jaipur University. I loves to write on technology and programming topics. Apart from this, I love to travel and enjoy the beauty of nature.