function demoover(m) {
obj=document.getElementById(m);
obj.style.display='block';
}

function demoout(m) {
var obj=document.getElementById(m);
obj.style.display='none';
}

function wyswietl(d) {
var tt='img/'+d;
var obj=document.getElementById('ekran');
obj.src=tt;
}

var img1=new Image();
img1.src='img/home_o.gif';
var img2=new Image();
img2.src='img/okol_o.gif';
var img3=new Image();
img3.src='img/offer_o.gif';