Multiple ScriptManager.RegisterStartupScript Issue

I have a Counter on a textbox done in Javascript like twitter that counts the text entered. Now It works fine. The Textboxes get field with data and after that i want to calculate the renmaining Text. i have a code for that after i bind the textbox. So i have this
 

  ScriptManager.RegisterStartupScript(Page, GetType(String), "FF", "InitializeCounter(" + "ctl00_ContentPlaceHolder_Main_Wizard1_Servitudes" + ",'ndacount2','bar','800');", True)
        ScriptManager.RegisterStartupScript(Page, GetType(String), "FF", "InitializeCounter(" + "ctl00_ContentPlaceHolder_Main_Wizard1_Introduction" + ",'NDAcount1','bar','800');", True)
 

 
and i realized that it only calculate the textbox counts for only the First one and fail to do it for the second one. Maybe it does not like multiple RegisterStartupScript
 
Thanks