var OsMessage='The Navigram Planner will only run under Windows. Unix and Apple are not supported.';
   var BrMessage='The Navigram Planner will only run under Internet Explorer 5+. '+'\n'+'Do you want more information on how to run Navigram in Firefox?';


   function BrowserOk() 					// checks browsertype and -version
   { 
    return ( (navigator.userAgent.indexOf('MSIE') != -1) && (navigator.appVersion >= '4') ) 
   }


   function OsOk() 						// tests operating system
   { 
    return (navigator.userAgent.indexOf('Win') != -1) 
   }


   function NavigramCanRun() 					// returns true if browsertype and os ok 
   { 
    if (!OsOk()) {alert(OsMessage)} 
    else if (!BrowserOk()) {if (confirm(BrMessage)==true) {window.location.href='../applications/sys/navrp/navigram-firefox.html'};};
    return (BrowserOk() && OsOk()) ;
   }


   function OpenNavigramWindow(theHref,theWidth,theHeight)	// opens a popup window for the navigram application
   {
    if (NavigramCanRun()) 
    {
     window.open(theHref,'Nav','status=yes,resizable=yes,width='+theWidth+',height='+theHeight);

    }
   }

   function OpenNavigram(theHref)				// opens navigram in the same window
   {
    if (NavigramCanRun()) 
    {
     top.document.location.href=theHref;
    }
   }