What should be the correct signature of the given method

What should be the correct signature of the given method

This is the function i have
FrmLoadingTimerID = setTimeout("UpdateKnl('"+ strType +"')",500);
where value of strytype is a string . In the UpdateKnl method switch
statement is there therefore strtype should be followed and ended with ''.
I want to send another parameter along with the function but not getting
the proper way to do so.
i have tried the following code
FrmLoadingTimerID = setTimeout("UpdateKnl('"+ strType +"',abc)",500);
and
FrmLoadingTimerID = setTimeout("UpdateKnl('"+ strType +"',+"abc")",500);
In both way the value is not passed as an undefined error is throw if i
try to assign the value of abc to other variable.