[Mapserver-users] How to show a delay image during launch of the VM

Wed Jun 11 06:36:43 PDT 2003

A few suggestions I have tried with middling success; much depends on the
browser viewing the applet.

1. If you can program in Java, write an applet (pseudo-applet?) that does
only three things (i) display a progress bar, simple animated gif image or
text messgae (ii) load the mapplet/jbox (iii) turn off the progress bar etc.
As the pseudo-applet loads much more quickly than a complex mapplet you
should see the message straight away, then there will be a pause while the
pseudo-applet loads its child applet. Don't forget to destroy the progress
bar because it will be there comsuming resources but hidden behind the
mapplet.
2. On load, have the page display the wait-message on a high layer and the
applet on an invisible layer. Then program a javascript timer to check
periodically for the applet (like if(!applet) continue . . . ). If the
applet is loaded (i.e. if(applet) evaluates to true) change the invisible
layer to visible and versus.
3. The HTML spec says there is an isActive property for objects, but I find
it doesn't always work. If it does, then write a function to execute with
the page body. For example, with <body onload="appletYet(myapplet)" > you
could have

function appletYet (appletName) {
    if (document && document[appletName] && document[appletName].isActive())
      showApplet(document[appletName]); /*a function of your creation*/
	dumpMessage(document.message); /*another of your functions*/
    else 
      setTimeout(appletYet, 500, appletName);
}/*end function appletYet

Best of luck (you'll probablly need it if my experience is a guide!).

-----Original Message-----
From: Mapserver [mailto:mapserver at gismap.ch]
Sent: Tuesday, June 10, 2003 2:06 PM
To: Mapserver-Userlist
Subject: [Mapserver-users] How to show a delay image during launch of
the VM

Hi list
I use mapplet/jbox and I have a little problem. Clients with slow computers
accessing my mapserver-website have to wait for a long time until the Sun-VM
ist loaded. During that time the users have a blank screen (!) for up to 20
seconds until the user-interface of mapserver appears.
I have to find a way to avoid a blank screen and to replace it with an
information or a little animation until the interface appears. Any ideas,
how this can be realized?

Thanks for help
Roman

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