let RecursiveFunction = function (arr, x, start, end) {

if (start > end) return false;

let mid=Math.floor((start + end)/2);

if (arr[mid]===x) return true;

if(arr[mid] > x)

return RecursiveFunction(arr, x, start, mid-1);

else

return RecursiveFunction(arr, x, mid+1, end);

let arr = [11, 13, 15, 17, 18, 19];

let x = 17;

if (RecursiveFunction(arr, x, 0, arr.length-1))

document.write("Element found!<br>");

else document.write("Element not found!<br>");

x = 6;

if (ReursiveFunction(arr, x, 0, arr.length-1))

document.write("Element found!<br>");

else document.write("Element not found!<br>");

</script>