JSFiddle - React, Tailwind, and code Playground

by vishagvj

HTML

<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">

<a href="https://www.w3schools.com/bootstrap/tryit.asp?filename=trybs_modal&stacked=h" id="leave">click here to leave the page</a>

<div id="myModal" class="modal fade" role="dialog">
  <div class="modal-dialog">

    <!-- Modal content-->
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal">&times;</button>
        <h4 class="modal-title">Modal Header</h4>
      </div>
      <div class="modal-body">
        <p>Changes made may not be saved.</p>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
      </div>
    </div>

  </div>
</div>

JavaScript

//$('#myModal').modal({ show: false})
var x=function(){
}
$("#leave").click(function(){
//$("#myModal").modal("show"); 

$(window).bind('beforeunload', function () {
        		//$("#myModal").modal("show");
        		//confirm("changes made may not be saved");
        		return 'Changes you made may not be Saved';
        	});


});