html javascript button click

1// Create variable for what you are trying to click
2let button = document.querySelector("#IDofItem");
3
4// Click the button
5
6if (button) {
7  button.click();
8}
9else {
10  console.log("Error");
11}

1document.getElementById('button').onclick = function() {
2   alert("button was clicked");
3};

1<script>
2  $(document).ready(function(){
3    $('#MyButton').click(function(){
4       CapacityChart();
5    });
6  });
7</script>
8
9<input type="button" value="Capacity Chart" id="MyButton" >

1<button onClick="alert('some thing to say');">click</button>