Binary_search.js

<script>
let recursiveFunction = function (arr, x, start, end) {
	
	// Base Condition
	if (start > end) return false;

	// Find the middle index
	let mid=Math.floor((start + end)/2);

	// Compare mid with given key x
	if (arr[mid]===x) return true;
		
	// If element at mid is greater than x,
	// search in the left half of mid
	if(arr[mid] > x)
		return recursiveFunction(arr, x, start, mid-1);
	else

		// If element at mid is smaller than x,
		// search in the right half of mid
		return recursiveFunction(arr, x, mid+1, end);
}

// Driver code
let arr = [1, 3, 5, 7, 8, 9];
let x = 5;

if (recursiveFunction(arr, x, 0, arr.length-1))
	document.write("Element found!<br>");
else document.write("Element not found!<br>");

x = 6;

if (recursiveFunction(arr, x, 0, arr.length-1))
	document.write("Element found!<br>");
else document.write("Element not found!<br>");
</script>