add js solution

Author: jackeyjia

problems/0096.不同的二叉搜索树.md

@@ -211,6 +211,23 @@ func numTrees(n int)int{
 }
 ```
 
+Javascript：
+```Javascript
+const numTrees =(n) => {
+    let dp = new Array(n+1).fill(0);
+    dp[0] = 1;
+    dp[1] = 1;
+
+    for(let i = 2; i <= n; i++) {
+        for(let j = 1; j <= i; j++) {
+            dp[i] += dp[j-1] * dp[i-j];
+        }
+    }
+
+    return dp[n];
+};
+```
+
 
 
 -----------------------