passing parmeters from parent to child popup program

[jmartin17]

I am having trouble understanding if field fRDNAM in the input statement below is empty in the parent program?

<input type="text" id="UXRDOC" name="UXRDOC" size="5" maxlength="5" value="<field name=UXRDOC>" style="background: yellow;"  onBlur="lookrdrno('<field name=UXRDOC>','<field name=fRDNAM>');"/>&nbsp;&nbsp;<span"> <b id="fRDNAM"><field name=fRDNAM>&nbsp;</b></span></a></p> 

http://www.jmartinassociates.net/images/refdoc.gif

what is causing fRDNAM to not be equal( <> ) RDNAM? No posrcd or getrcd has been issued at that point?
Both of them is empty at if(fRDNAM <> RDNAM) compare time?

func lookbook()
{
 getparmset(fRDNAM,fRDNUM);
 if(fRDNAM <> RDNAM) 
 {
  RDNAM = fRDNAM;  
  alert ("stmt 70 fRDNAM not blank IS " + fRDNAM + " - " + numtoalpha(fRDNUM));

 http://www.jmartinassociates.net/images/stmt70.gif
  
  
 }
 if(RDNUM == 0)
 {
  RDNUM = fRDNUM;  
  alert ("stmt 76 fRDNUM is zero " + fRDNAM + " - " + numtoalpha(fRDNUM));

http://www.jmartinassociates.net/images/stmt76.gif

 
 }
 
 posrcd(pbrdocp,DfKlist); 
 getrcd(pbrdocp, Dfklist);
 alert ("STMT 83  IS " + RDNAM + " - " + numtoalpha(RDNUM));

http://www.jmartinassociates.net/images/stmt83.gif

I am still having trouble understanding how to effectively understand and debug javascript?

How do you test for blank or zero parmeters when passed to program?

[toicontien]

You appear to be using JScript, Microsoft's version of JavaScript. Can we please see all the HTML and JavaScript? I can't tell what you're trying to accomplish with the code you've given.