onclick javascript in button code example

Example 1: javascript onclick

document.getElementById("myBtn").addEventListener("click", function() {
  alert("Hello World!");
});

Example 2: run a function when a button has the onclick

<script>
function myFunction() {
  alert("ALERT THIS FUNCTION HAS RUNNED");
}
</script>
<button onclick="myFunction">click to run function</button>

Example 3: javascript button onclick

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

Example 4: javascript onclick button

var button = document.querySelector('button');
button.onclick = function() {
  //do stuff
}