Although its not a good idea to disable F5 key you can do it in JQuery as below.
<script type="text/javascript">
function disableF5(e) { if ((e.which || e.keyCode) == 116 || (e.which || e.keyCode) == 82) e.preventDefault(); };
$(document).ready(function(){
$(document).on("keydown", disableF5);
});
</script>
Hope this will help!