if (document.images){

mtb_over = new Image
mtb_up = new Image

strada_over = new Image
strada_up = new Image    

componenti_over = new Image
componenti_up = new Image

abbigliamento_over = new Image
abbigliamento_up = new Image

arrowup_over = new Image
arrowup_up = new Image

arrowdown_over = new Image
arrowdown_up = new Image

arrowupb_over = new Image
arrowupb_up = new Image

arrowdownb_over = new Image
arrowdownb_up = new Image

// sources

mtb_over.src = "images/mtb_over.gif"
mtb_up.src = "images/mtb.gif"

strada_over.src = "images/strada_over.gif"
strada_up.src = "images/strada.gif"

componenti_over.src = "images/componenti_over.gif"
componenti_up.src = "images/componenti.gif"

abbigliamento_over.src = "images/abbigliamento_over.gif"
abbigliamento_up.src = "images/abbigliamento.gif"

arrowup_over.src = "images/frecciasu_over.gif"
arrowup_up.src = "images/frecciasu_up.gif"

arrowdown_over.src = "images/frecciagiu_over.gif"
arrowdown_up.src = "images/frecciagiu_up.gif"

arrowupb_over.src = "images/frecciasu_over.gif"
arrowupb_up.src = "images/frecciasu_up.gif"

arrowdownb_over.src = "images/frecciagiu_over.gif"
arrowdownb_up.src = "images/frecciagiu_up.gif"


}       

function rollover (pulsante){
	imgSwitch=eval(pulsante + "_over.src");
	document[pulsante].src=imgSwitch
}

function rollout (pulsante){
	imgSwitch=eval(pulsante + "_up.src");
	document[pulsante].src=imgSwitch
}