I am new to scripting and am trying to get this script to run on the record load of a customer file but I am get a definition error.  I need to confirm that my field name is correct and also how to make sure it runs during the custrec load and not just in edit mode.  Any help please??  Thank you!!!

function creditalert(){
var custrec_oncredithold = pnvl(nlapiGetFieldValue('custrec_oncredithold'), false);
if (custrec_oncredithold'), true{
  if(!confirm('Customer is on Credit Hold!. Do you want to continue?')) return false;
}
return true;
}