if (document.images) {
    button_main_up       = new Image();
    button_main_up.src   = "images/navi_main_high.gif" ;
    button_main_down      = new Image();
    button_main_down.src   = "images/navi_main_normal.gif" ;

    button_about_up       = new Image();
    button_about_up.src   = "images/navi_about_high.gif" ;
    button_about_down      = new Image();
    button_about_down.src   = "images/navi_about_normal.gif" ;

    button_blog_up       = new Image();
    button_blog_up.src   = "images/navi_blog_high.gif" ;
    button_blog_down      = new Image();
    button_blog_down.src   = "images/navi_blog_normal.gif" ;

    button_forums_up       = new Image();
    button_forums_up.src   = "images/navi_forums_high.gif" ;
    button_forums_down      = new Image();
    button_forums_down.src   = "images/navi_forums_normal.gif" ;

    button_playground_up       = new Image();
    button_playground_up.src   = "images/navi_playground_high.gif" ;
    button_playground_down      = new Image();
    button_playground_down.src   = "images/navi_playground_normal.gif" ;

    button_download_up       = new Image();
    button_download_up.src   = "images/download_high.png" ;
    button_download_down      = new Image();
    button_download_down.src   = "images/download_normal.png" ;
}

function buttondown( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "_down.src" );
    }
}
function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "_up.src" );
    }
}

function move_login_box()
{
	// 603, 740
	var loginbox = document.getElementById('login_box');
	if( loginbox )
	{
		var extra_move = ( document.body.clientWidth - 740 ) * 0.5;
		
		loginbox.style.left = 614 + extra_move;
		loginbox.style.top = 0;
	}
}