function open_window(image){
	var top=(screen.height-800)/2;
  	var left=(screen.width-800)/2;
	/*window.open(image,'_blank','width=770, height=500, top='+PosY+',left='+PosX);*/
	
  	window.open(image,"","resizable=yes,top="+top+",left="+left+",width=800,height=600");

}

function show_hide_menu( id ) {
 var p = document.getElementById(id);
	for( var i = 0; i < 5; i++ ) {
	 var e = document.getElementById( 'menu'+i );
	 if ( e ) {
	  e.style.visibility='hidden';
	  e.style.display='none';
	 }
	}
 if( p ) {
	 p.style.visibility='visible';
	 p.style.display='block';
	}
}