How to display the value of a variable within javascript?

Here I want to trap and alert or echo the value of var thisCount The problem is I cant display the value.I'd tried many ways but no luck.

<script>

$(document).on("click", ".open-dialog", function () {

   var thisCount = $(this).data('count');

//this place the code

   $(".modal-body #count").val( thisCount);

});

via Chebli Mohamed