diff --git a/09_dynamic_programming/javascript/01_longest_common_subsequence.js b/09_dynamic_programming/javascript/01_longest_common_subsequence.js
new file mode 100644
index 0000000..f1054d0
--- /dev/null
+++ b/09_dynamic_programming/javascript/01_longest_common_subsequence.js
@@ -0,0 +1,7 @@
+if (word_a[i] === word_b[j]) {
+  // The letters match
+  cell[i][j] = cell[i-1][j-1] + 1;
+} else {
+  // The letters don't match
+  cell[i][j] = Math.max(cell[i-1][j], cell[i][j-1]);
+}