var screenW = 640, screenH = 480;

if ( parseInt( navigator.appVersion )>3 ) {
	screenW = screen.width;
	screenH = screen.height;

} else if (	navigator.appName == "Netscape"
    		&& parseInt(navigator.appVersion) == 3
    		&& navigator.javaEnabled() ){

	var jToolkit = java.awt.Toolkit.getDefaultToolkit();
	var jScreenSize = jToolkit.getScreenSize();
	screenW = jScreenSize.width;
	screenH = jScreenSize.height;
}