Thanks,
I insert it like this and it work,
document.write ("?campaignid=1&source=food");
What I need to insert in this line:
document.write ("&your target variable={your target value for variable}");
and please, can I dispaly all the banner with the same channel, but witout the campaignid? I try to use it like this but it didnot work:
document.write ("&source=food");