// JavaScript Document
// JavaScript Document
var n = 4;
var f = false;
var b = new Array;
function prel(){

   	if(document.images) {
	  for(i=1;i<=n;i++)
               {str = 'buttons/t' + i + '_a.gif';
               b[i-1] = new Image();
               b[i-1].src = str;
}f = true;
 		}
}

function on(im){
	if (document.images && (f == true)) 
		{document.images[im].src="buttons/"+im+"_a.gif";}
		
}
function off(im){
	if (document.images && (f == true))
		{document.images[im].src = "buttons/"+im+".gif";}
}
function on_t(im){
	if (document.images && (f == true)) 
		{document.images[im].src="buttons/t1_a.gif";}
		
}
function off_t(im){
	if (document.images && (f == true))
		{document.images[im].src = "buttons/t1.gif";}
}

function nav_on (id) 
{
document.getElementById(id).background = 'images/podsvetka.gif';
}

function nav_off (id) 
{
document.getElementById(id).background = '';
}