var step=1
var image1=new Image()
var image2=new Image()

function slide_start(katalog) {
    image1.src="images/header/main_01.gif"
    image2.src="images/header/main_02.gif"

    step=1
    slide()
}

function slide(){
//if browser does not support the image object, exit.
if (!document.images)
return
document.images.slide.src = eval("image"+step+".src")
if (step<2)
step++
else
step=1
//call function "slideit()" every 2.5 seconds
setTimeout("slide()",4000)
}