Answers for "how to add js script for each click"

button functions html

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

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...
}