Added Interpolation and exponential searches in the javascript repo

Search/ExponentialSearch.js

@@ -0,0 +1,61 @@
+/*
+ * Exponential Search
+ *
+ * The algorithm consists of two stages. The first stage determines a 
+ * range in which the search key would reside if it were in the list. 
+ * In the second stage, a binary search is performed on this range.
+ * 
+ *
+ *  
+ */
+
+function binarySearch(arr, x, floor, ceiling) {
+    // Middle index
+    let mid = Math.floor((floor + ceiling) / 2);
+
+    // If value is at the mid position return this position
+    if (arr[mid] === x) {
+        return mid;
+    }
+
+    if(floor > ceiling) return -1;
+
+    // If the middle element is great than the value 
+    // search the left part of the array
+    if (arr[mid] > value) {
+        return binarySearch(arr, value, floor, mid - 1);
+        //If the middle element is lower than the value
+        //search the right part of the array
+    } else {
+        return binarySearch(arr, value, mid + 1, ceiling);
+    }
+
+
+}
+
+
+function exponentialSearch(arr, length, value) {
+    // If value is the first element of the array return this position 
+    if (arr[0] == value) {
+        return 0;
+    }
+
+    // Find range for binary search 
+    let i = 1;
+    while (i < length && arr[i] <= value) {
+        i = i * 2;
+    }
+
+    // Call binary search for the range found above 
+    return binarySearch(arr, value, i / 2, Math.min(i, length));
+}
+
+let arr = [2, 3, 4, 10, 40, 65 , 78 , 100];
+let value = 78;
+let result = exponentialSearch(arr, arr.length, value);
+
+if (result < 0) {
+    console.log("Element not found");
+} else {
+    console.log("Element found at position :" + result);
+}