html code to display filed on button click js code example

Example 1: button functions html

<script>
 function myFunction() {
   alert("ALERT");
 }
</script>
<button onclick="myFunction">Click</button>

Example 2: javascript onclick

// The element id (TheElementID) and var name (myElement) can be named anything.
var myElement = document.getElementByID('TheElementID');
myElement.onclick = function() {
	// Carry out a function here...
}