Hi Dario,
I fixed my error ("up_down" field), but it still has error when you first page loaded -->
http://www.gls.com.vn:8080/priceonline/test.htm

Here my directory :
C:\Lightstreamer\pages\priceonline\test.htm
C:\Lightstreamer\pages\priceonline\js\prototype.js
C:\Lightstreamer\pages\priceonline\js\scriptaculou s.js
C:\Lightstreamer\pages\priceonline\js\controls.js
C:\Lightstreamer\pages\priceonline\js\slider.js

and my slider can't show.