Trouble with code for replacing value in MSH

[brusstoc]

I hate to admit it, but I surrender. I must be missing something simple in the formatting of this javascript code to change a value in an MSH header. I looked around and found this code from late last year in the forums:

var obr21 = msg['OBR']['OBR.2']['OBR.2.1'].toString(); //assign the obr21 value to a variable
obr21 = obr21.replace("-0","-2"«»); //perform replacement on variable
msg['OBR']['OBR.2']['OBR.2.1'] = obr21; //place the new value back into the message

I tried duplicating that - as it looked like it would work. However, the messages fly right through the channel without the slightest change in MSH3.

"MY" CODE:

var msh3 = msg['MSH']['MSH.3']['MSH.3.1'].toString();
msh3=msh3.replace("oldValue","newValue"«»);
msg['MSH']['MSH.3']['MSH.3.1']=msh3;

Please tell me what I am missing, I beg of you.

[brusstoc]

Re:Trouble with code for replacing value in MSH

Hey, Chris L helped me figure this out (working with a project with the company)

if (msg['MSH']['MSH.3']['MSH.3.1'].toString() == "oldValue"){
msg['MSH']['MSH.3']['MSH.3.1'] = "newValue";
}

Also, I had the Destination template stating ${message.rawData} and changed that to ${message.encodedData}.