diff --git a/.gitignore b/.gitignore
index b7dfd6457a..c6b4f54e91 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,4 +7,5 @@ out/
*.vscode/
src/main/java/com/fishercoder/solutions/_99999RandomQuestions.java
src/main/java/com/fishercoder/solutions/_Contest.java
-.project
\ No newline at end of file
+.project
+bin
\ No newline at end of file
diff --git a/javascript/_17.js b/javascript/_17.js
new file mode 100644
index 0000000000..f950e696de
--- /dev/null
+++ b/javascript/_17.js
@@ -0,0 +1,43 @@
+function letterCombinations(digits) {
+ // If the input is an empty string, return an empty array.
+ if (digits.length === 0) {
+ return [];
+ }
+
+ // Mapping of digits to letters as per the telephone keypad using a javascript dictionary.
+ const digitToChar = {
+ '2': ['a', 'b', 'c'],
+ '3': ['d', 'e', 'f'],
+ '4': ['g', 'h', 'i'],
+ '5': ['j', 'k', 'l'],
+ '6': ['m', 'n', 'o'],
+ '7': ['p', 'q', 'r', 's'],
+ '8': ['t', 'u', 'v'],
+ '9': ['w', 'x', 'y', 'z']
+ };
+
+ // Resultant array to store all possible combinations
+ const result = [];
+
+ // Backtracking function to generate combinations
+ function backtrack(index, currentCombination) {
+ // if the current combination has the same length as the input digits.
+ if (index === digits.length) {
+ result.push(currentCombination);
+ return;
+ }
+
+ // Get the letters that the current digit maps to.
+ let letters = digitToChar[digits[index]];
+
+ // Loop through the letters and call backtrack recursively for the next digit.
+ for (let letter of letters) {
+ backtrack(index + 1, currentCombination + letter);
+ }
+ }
+
+ // Start backtracking from the first digit (index 0) with an empty string as the initial combination.
+ backtrack(0, '');
+
+ return result;
+};
diff --git a/javascript/_3.js b/javascript/_3.js
new file mode 100644
index 0000000000..2218e25361
--- /dev/null
+++ b/javascript/_3.js
@@ -0,0 +1,23 @@
+function lengthOfLongestSubstring(s) {
+ // Using the "sliding window" data structure.
+ // Create a javascript set to store unique characters.
+ let charSet = new Set();
+ let left = 0; // Left pointer of the sliding window.
+ let maxLength = 0;
+
+ // This moves the right pointer of the sliding window.
+ for (let right = 0; right < s.length; right++) {
+ // If the character at the right pointer is already in the set, move the left pointer.
+ while (charSet.has(s[right])) {
+ charSet.delete(s[left]);
+ left++;
+ }
+ // Add the current character at the right pointer to the set.
+ charSet.add(s[right]);
+
+ // Update the maximum length of substring without repeating characters.
+ maxLength = Math.max(maxLength, right - left + 1);
+ }
+
+ return maxLength;
+}
\ No newline at end of file
diff --git a/paginated_contents/algorithms/1st_thousand/README.md b/paginated_contents/algorithms/1st_thousand/README.md
index d9601619b0..24e367d524 100644
--- a/paginated_contents/algorithms/1st_thousand/README.md
+++ b/paginated_contents/algorithms/1st_thousand/README.md
@@ -796,7 +796,7 @@
| 20 | [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_20.java) | [:tv:](https://www.youtube.com/watch?v=eBbg5pnq5Zg) | Easy | Stack
| 19 | [Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_19.java) | [:tv:](https://youtu.be/Kka8VgyFZfc) | Medium | Linked List
| 18 | [4 Sum](https://leetcode.com/problems/4sum/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_18.java) || Medium | Two Pointers
-| 17 | [Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_17.java) || Medium | Backtracking
+| 17 | [Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_17.java), [Javascript](https://github.com/fishercoder1534/Leetcode/blob/master/javascript/_17.js) || Medium | Backtracking
| 16 | [3Sum Closest](https://leetcode.com/problems/3sum-closest/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_16.java) || Medium | Two Pointers
| 15 | [3Sum](https://leetcode.com/problems/3sum/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_15.java), [C++](../master/cpp/_15.cpp) | [:tv:](https://www.youtube.com/watch?v=jeim_j8VdiM) | Medium | Two Pointers, Binary Search
| 14 | [Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_14.java) | [:tv:](https://www.youtube.com/watch?v=K1ps6d7YCy4) | Easy
@@ -810,6 +810,6 @@
| 6 | [ZigZag Conversion](https://leetcode.com/problems/zigzag-conversion/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_6.java) | | Easy |
| 5 | [Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_5.java) | | Medium |
| 4 | [Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_4.java), [C++](../master/cpp/_4.cpp) | | Hard | Divide and Conquer
-| 3 | [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_3.java), [C++](../master/cpp/_3.cpp) | | Medium | HashMap, Sliding Window
+| 3 | [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_3.java), [C++](../master/cpp/_3.cpp), [Javascript](https://github.com/fishercoder1534/Leetcode/blob/master/javascript/_3.js) | | Medium | HashMap, Sliding Window
| 2 | [Add Two Numbers](https://leetcode.com/problems/add-two-numbers/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_2.java) | | Medium | LinkedList
| 1 | [Two Sum](https://leetcode.com/problems/two-sum/) | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_1.java), [C++](../master/cpp/_1.cpp), [Javascript](../master/javascript/_1.js) | [:tv:](https://www.youtube.com/watch?v=kPXOr6pW8KM&t=) | Easy | HashMap
\ No newline at end of file