JSFiddle - React, Tailwind, and code Playground

HTML

<body>
<input id="Hidden1" type="hidden" />
</body>

JavaScript

(function() {
  if (confirm('Are you sure you want to proceed?') == true) 
  { 
    document.getElementById('Hidden1').value = 'yes'; 
  } 
  else   
  {  
    document.getElementById('Hidden1').value = 'no';
	}
})();