diff --git a/leetcode/20 - validparenthesis/valid-parenthesis.js b/leetcode/20 - validparenthesis/valid-parenthesis.js
new file mode 100644
index 0000000..5aec27c
--- /dev/null
+++ b/leetcode/20 - validparenthesis/valid-parenthesis.js	
@@ -0,0 +1,26 @@
+const OBJECT_MAPPING = {
+  ')': '(',
+  ']': '[',
+  '}': '{',
+}
+
+var isValid = function (s) {
+  const opens = []
+  for (c of s) {
+    if (c === '(' || c === '[' || c === '{') {
+      opens.push(c)
+    } else {
+      if (opens.length === 0) {
+        return false;
+      }
+      const lastOpen = opens[opens.length - 1];
+      if (OBJECT_MAPPING[c] != lastOpen) {
+        return false
+      } else {
+        opens.pop();
+      }
+    }
+  }
+
+  return opens.length === 0
+};
\ No newline at end of file