function showtab(btnid,tabid,tabnumber)
{
	for (i = 1;i<=tabnumber;i++)
	{
	    document.getElementById(tabid+"_btn"+i).className = "navzi";
		document.getElementById(tabid+"_btn"+i).style.backgroundRepeat="no-repeat";
		
		document.getElementById(tabid+"_sub"+i).style.display= "none";
		
	}
	document.getElementById(tabid+"_btn"+btnid).className = "navzi";
			  document.getElementById(tabid+"_btn"+btnid).style.backgroundRepeat="no-repeat";
	document.getElementById(tabid+"_sub"+btnid).style.display ="";
}