if(document.all)
	document.execCommand("BackgroundImageCache", false, true);

var _count_anim = 0;
var _file_to_display = 1;
var _min_file_id = 1;
var _max_file_id = 9;

function change_header_bg() {
	_file_to_display++;
	if(_file_to_display>_max_file_id) {
		_file_to_display = _min_file_id;
		_count_anim++;
	}
	var img_filename = 'images/header_anim/'+_file_to_display+'.jpg';
	document.getElementById('header').style.backgroundImage = "url("+img_filename+")";
	
	if(_count_anim == 0) {
		//preload next image
		var next_file_to_display = _file_to_display+2;
		var next_img_filename = 'images/header_anim/'+next_file_to_display+'.jpg';
		MM_preloadImages(next_img_filename);
	}
}

function launch_header_anim() {
	//preload 2 images, then launch the animation
	var next_file_to_display = _file_to_display+1;
	var next_img_filename = 'images/header_anim/'+next_file_to_display+'.jpg';
	MM_preloadImages(next_img_filename);
	var next_file_to_display = _file_to_display+2;
	var next_img_filename = 'images/header_anim/'+next_file_to_display+'.jpg';
	MM_preloadImages(next_img_filename);
	
	setInterval ( "change_header_bg()", 3000 );
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}