diff --git a/problems/0039.组合总和.md b/problems/0039.组合总和.md
index e3e79295..0eba785f 100644
--- a/problems/0039.组合总和.md
+++ b/problems/0039.组合总和.md
@@ -292,7 +292,32 @@ class Solution:
 ```
 Go：
 
+JavaScript
+```js
+var strStr = function (haystack, needle) {
+  if (needle === '') {
+    return 0;
+  }
 
+  let hayslen = haystack.length;
+  let needlen = needle.length;
+
+  if (haystack === '' || hayslen < needlen) {
+    return -1;
+  }
+
+  for (let i = 0; i <= hayslen - needlen; i++) {
+    if (haystack[i] === needle[0]) {
+      if (haystack.substr(i, needlen) === needle) {
+        return i;
+      }
+    }
+    if (i === hayslen - needlen) {
+      return -1;
+    }
+  }
+};
+```
 
 
 -----------------------