diff --git a/520.detect-capital.js b/520.detect-capital.js
new file mode 100644
index 0000000..923cd2a
--- /dev/null
+++ b/520.detect-capital.js
@@ -0,0 +1,18 @@
+/**
+ * URL of this problem
+ * https://leetcode.com/problems/detect-capital/
+ */
+
+/**
+ * @param {string} word
+ * @return {boolean}
+ */
+var detectCapitalUse = function (word) {
+	const AllCapitalLetter = word.toUpperCase();
+	const AllLowerCaseLetter = word.toLowerCase();
+	const FirstCapitalLetter = word.charAt(0).toUpperCase() + AllLowerCaseLetter.slice(1);
+
+	if (AllCapitalLetter === word || AllLowerCaseLetter === word || FirstCapitalLetter === word) return true;
+
+	return false;
+};