change button color on click javascript code example

Example 1: onclick change text color javascript

<script>

    document.getElementById('change').onclick = changeColor;   

    function changeColor() {
        document.body.style.color = "purple";
        return false;
    }   

</script>

Example 2: change background color on button click in javascript

<style>
  .bg1 {
  	background-color: red;
  }
</style>

<button id="btnChangebgColor" />

<script>
  	$(document).ready(function(){
      $("#btnChangebgColor").click(function() {
        $(this).addClass(".bg1");
      }); 
	}
</script>