Prevent pollution

Prevent window pollution by create a new variable named window.

此腳本不應該直接安裝，它是一個供其他腳本使用的函式庫。欲使用本函式庫，請在腳本 metadata 寫上： // @require https://update.greasyfork.org/scripts/17562/110734/Prevent%20pollution.js 

var _win = window;
eval('var window = {};');