function hide_content()
{
	var hide = new Array( "america", "europe", "asia", "africa" );
	for ( i = 0; i < hide.length; i++ ) 
		document.getElementById( hide[i] ).style.display = "none";
}
function show_content( elem )
{		
	hide_content();
	document.getElementById( elem ).style.display = "block";  
}
function preload_imgaes()
{
	var path = "./img/"; 
	i1 = new Image( 186, 28 );
	i1.src = path + "ap_on.png";
	i2 = new Image( 186, 28 );
	i2.src = path + "eu_on.png";
	i3 = new Image( 186, 28 );
	i3.src = path + "me_on.png";
	i4 = new Image( 186, 28 );
	i4.src = path + "na_on.png";
	i5 = new Image( 753, 280 );
	i5.src = path + "menu_bg.png";
}