diff --git a/javascript/_747.js b/javascript/_747.js
new file mode 100644
index 0000000000..c5366a9fd0
--- /dev/null
+++ b/javascript/_747.js
@@ -0,0 +1,16 @@
+var dominantIndex = function (nums) {
+  var maxdata = -1;
+  var maxIndex = -1;
+  for (var i = 0; i < nums.length; i++) {
+    if (nums[i] > maxdata) {
+      maxdata = nums[i];
+      maxIndex = i;
+    }
+  }
+  for (var i = 0; i < nums.length; i++) {
+    if (i != maxIndex && nums[i] * 2 > maxdata) {
+      return -1;
+    }
+  }
+  return maxIndex;
+};