diff --git a/src/leecode/javascript/4.寻找两个正序数组的中位数.js b/src/leecode/javascript/4.寻找两个正序数组的中位数.js
new file mode 100644
index 0000000..8d820ce
--- /dev/null
+++ b/src/leecode/javascript/4.寻找两个正序数组的中位数.js
@@ -0,0 +1,42 @@
+/*
+ * @lc app=leetcode.cn id=4 lang=javascript
+ *
+ * [4] 寻找两个正序数组的中位数
+ */
+
+// @lc code=start
+/**
+ * @param {number[]} nums1
+ * @param {number[]} nums2
+ * @return {number}
+ */
+//o(n) = m+n
+var findMedianSortedArrays = function (nums1, nums2) {
+  let index1 = 0;
+  let index2 = 0;
+  let cur = 0;
+  const needTow = (nums1.length + nums2.length) % 2 === 0;
+  const mid = needTow ? (nums1.length + nums2.length) / 2 : Math.ceil((nums1.length + nums2.length) / 2);
+  let index = 0;
+  while (index < mid) {
+    if ((index1 < nums1.length && nums1[index1] <= nums2[index2]) || index2 >= nums2.length) {
+      cur = nums1[index1];
+      index1++;
+    } else {
+      cur = nums2[index2];
+      index2++;
+    }
+    index++;
+  }
+  if (needTow) {
+    if ((index1 < nums1.length && nums1[index1] <= nums2[index2]) || index2 >= nums2.length) {
+      cur = (cur + nums1[index1]) / 2;
+    } else {
+      cur = (cur + nums2[index2]) / 2;
+    }
+  }
+  return cur;
+};
+
+console.log(findMedianSortedArrays([3, 4], []));
+// @lc code=end