button javascript event with function code example

Example 1: how to add onclick event in javascript

var element = document.getElementById("elem");
element.onclick = function(event) {
  console.log(event);
}

Example 2: button click function in js

<script>
  $(document).ready(function(){
    $('#MyButton').click(function(){
       CapacityChart();
    });
  });
</script>

<input type="button" value="Capacity Chart" id="MyButton" >