add js solution to leetcode: No.80 (#365)

* add js solution to leetcode: No.80

* change formatting

Author: 0xtch

solution/0000-0099/0080.Remove Duplicates from Sorted Array II/README.md

@@ -147,6 +147,27 @@ public class Solution {
 }
 ```
 
+### **JavaScript**
+
+``` JavaScript
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var removeDuplicates = function (nums) {
+    if (nums.length == 0) return 0;
+    let len = nums.length;
+    let j = 0;
+    for (let i = 0; i < nums.length - 1; i++) {
+        if (nums[i] != nums[i - 1] || nums[i] != nums[i + 1]) {
+            nums[j++] = nums[i];
+        }
+    }
+    nums[j] = nums[len - 1];
+    return j + 1;
+};
+```
+
 ### **...**
 
 ```

solution/0000-0099/0080.Remove Duplicates from Sorted Array II/README_EN.md

@@ -125,6 +125,28 @@ public class Solution {
         return cur;
     }
 }
+```
+
+### **JavaScript**
+
+``` JavaScript
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var removeDuplicates = function (nums) {
+    if (nums.length == 0) return 0;
+    let len = nums.length;
+    let j = 0;
+    for (let i = 0; i < nums.length - 1; i++) {
+        if (nums[i] != nums[i - 1] || nums[i] != nums[i + 1]) {
+            nums[j++] = nums[i];
+        }
+    }
+    nums[j] = nums[len - 1];
+    return j + 1;
+};
+```
 
 ### **...**
 
@@ -133,4 +155,3 @@ public class Solution {
 ```
 
 <!-- tabs:end -->
-```

solution/0000-0099/0080.Remove Duplicates from Sorted Array II/Solution.js

@@ -0,0 +1,16 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var removeDuplicates = function (nums) {
+    if (nums.length == 0) return 0;
+    let len = nums.length;
+    let j = 0;
+    for (let i = 0; i < nums.length - 1; i++) {
+        if (nums[i] != nums[i - 1] || nums[i] != nums[i + 1]) {
+            nums[j++] = nums[i];
+        }
+    }
+    nums[j] = nums[len - 1];
+    return j + 1;
+};