diff --git a/js/back.js b/js/back.js
deleted file mode 100644
index 2cfab3f..0000000
--- a/js/back.js
+++ /dev/null
@@ -1,6 +0,0 @@
-
-window.onload = function(){
-var ele = document.getElementsByTagName("body")[0];
-var n = Math.floor(Math.random() * 3); // 3枚の画像がある場合
-ele.style.backgroundImage = "url(img/titleimg/"+n+".png)";
-}