function preloadImages(url,pictures){    
    if (document.images) {        
        preload_image_object = new Image();
        image_url = new Array();
        image_url = pictures.split(",");
        
        var i = 0;
        for(i=0; i<=image_url.length-1; i++){
            preload_image_object.src = url+image_url[i];
        }
    }
} 

function changeClassO(style){
    style.className=style.className+'_o';
}
function changeClass(style){
    style.className=style.className.substring(0,style.className.length-2);
}

function changeImageOver(image,over){
	var ext=image.src.substring(image.src.length-4,image.src.length);
	var file=image.src.substring(0,image.src.length-4);
	image.src=file+over+ext;
}

function changeImage(image,over){
	var over_size=over.length;
	var ext=image.src.substring(image.src.length-4,image.src.length);
	var file=image.src.substring(0,image.src.length-(over_size+4));
	image.src=file+ext;
}

function submenu_show(obj){
	obj.getElementsByTagName('span')[1].style.display = 'block';
}

function submenu_hide(obj){
	obj.getElementsByTagName('span')[1].style.display = 'none';
}