each time button is pressed call new function code example

Example 1: 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 2: how to make a button do different functions on different clicks

var callOne = true;

function one() {
   alert('Call one');
}

function two() {
   alert('Call two');
}

function call(){
   if(callOne) one();
  else two();
  callOne = !callOne;
}