Catch error in javascript when using SAP script

Question

All,
I have a issue when using Javascript to control the SAP GUI in that I get a "syntax Error" raised by Internet Explorer if I attempt to get the SAPGUI runtime object from the runtime object table if SAP is not already running.
For example:
I have a javascript function embedded in a web page as follows:
<script type="text/javascript">
function displaymessage()
var sapgui;
var application;
var connection;
if (typeof(application) == "undefined")
   sapgui      = GetObject("SAPGUI");
   application = sapgui.GetScriptingEngine();
if (typeof(connection) == "undefined")
   connection = application.children(0);
if (typeof(session) == "undefined")
   session = connection.children(0);
if (typeof(WScript) != "undefined")
   WScript.connectObject(session, "on");
   WScript.connectObject(application, "on");
session.findById("wnd[0]/tbar[0]/okcd").text = "fb50";
session.findById("wnd[0]").sendVKey(0);
session.findById("wnd[1]/usr/ctxtBKPF-BUKRS").text = "0001";
session.findById("wnd[1]/usr/ctxtBKPF-BUKRS").caretPosition = 4;
session.findById("wnd[1]").sendVKey(0);
</script>
I have a simple HTML page with a button on it that calls the function.
If I have already launched SAP GUI and logged in the code works fine and atuomatically navigates me to FB50.
If SAP is not active and logged in then I get a syntax error!  The error is raised by IE when the GetObject("SAPGUI") is executed.
Can anyone please help by either:
a) explaining how I can catch this error in javascript
b) suggesting a different way to call the GetObject
c) suggesting a way that I can auto launch SAP to log people in if it is not already active.
Note - Using VB is not an option as I need to embed the working Javascript code in a Siebel thin client application which only uses Javascript.
All help welcome. Thanks

Answer 1

Hey Gunter,
Thanks much, that did work.
The other error I spoke of was fixed with the new database, so apparently the two errors I spoke of weren't related.
You seem to be a good help to this forum, thank you for that.... fixing my problem relieved me from much stress.
Cheers,
Derek Miller
Dreamweaver Enthusiast