var buttPath = "images/but/";

var buttNorm = new Array (
	"but_home.gif",
	"but_about.gif",
	"but_brands.gif",
	"but_news.gif",
	"but_contact.gif",
	"but_about_1.gif",
	"but_about_2.gif",
	"but_about_3.gif",
	"but_about_4.gif",
	"but_news_1.gif",
	"but_news_2.gif",
	"but_about_5.gif",
	"but_contact_1.gif",
	"but_contact_2.gif",
	"but_marelli.gif"
);

var buttOver = new Array (
	"but_home_roll.gif",
	"but_about_roll.gif",
	"but_brands_roll.gif",
	"but_news_roll.gif",
	"but_contact_roll.gif",
	"but_about_1_roll.gif",
	"but_about_2_roll.gif",
	"but_about_3_roll.gif",
	"but_about_4_roll.gif",
	"but_news_1_roll.gif",
	"but_news_2_roll.gif",
	"but_about_5_roll.gif",
	"but_contact_1_roll.gif",
	"but_contact_2_roll.gif",
	"but_marelli_roll.gif"
);
	
var buttNorm = preload_images ( buttPath, buttNorm );
var buttOver = preload_images ( buttPath, buttOver );

function preload_images ( img_path, img_array )
{
    var images = new Array;

    for ( var img_num=0; img_num<img_array.length; img_num++ ) {

        images[img_num] = new Image ();
        var url = img_path + img_array[img_num];
        images[img_num].src = url;
    }

    return ( images );
}

function buttonOver ( buttNum ) {
    if ( document.images ) {
        var objectID = document.images[ 'but' + buttNum ];
        objectID.src = eval( "buttOver[" + buttNum + "].src");
    }		
}

function buttonOut ( buttNum ) {
    if ( document.images ) {
        var objectID = document.images[ 'but' + buttNum ];
        objectID.src = eval( "buttNorm[" + buttNum + "].src");
    }
}