bunch of proxies of sadly been taken down but I added a new one for a test. (New Updates Aswell!)
Copy all the text below made by FUNULTIMATE :)
javascript:eval('function calc(){_o=prompt(_t,_z);if(_o!=\'\'&&_o!=null&&_o.toUpperCase()==_o.toLowerCase())_z=eval(_o);}');_t='Calculator\nMade By FUNULTIMATE\nInsert the equation you wish to calculate:';_z='';calc();while(_o!=''&&_o!=null&&_o.toUpperCase()==_o.toLowerCase())calc()