I have a custom Object to track registrations against an Opportunity in Salesforce. I created a script so that clicking a button would change the stage of the Opportunity and then go through each Registration and change the status if it was Pending.
When I test it on an Opportunity with 3 registrations, it seems to work every time. When I use it on an Opportunity with 7 registrations, it is changing registrations that it shouldn't be.
I store the conditions back to the Registration and it looks as though it should be ignoring the record, but it gets updated.

{!REQUIRESCRIPT("/soap/ajax/19.0/connection.js")} //Required for SalesForce connection 

//Make sure not entering by mistake 
input_box = confirm ("Are you sure you want to update the workshop to Attended?") 

if (input_box==true) 

{ 
 var url = parent.location.href; //string for the URL of the current page 
 //Set up the connection and grab the current Opportunity ID 
 var conn; 
 conn = sforce.connection; 
 var opp = "{!Opportunity.Id}"; 
 var oppname= "{!Opportunity.Name}"; 

 //Get the Registration ID's for all Registrants to this Opportunity 
 var qr = conn.query("Select Registration__c.Id, Registration__c.Workshop_Cancelled__c, Registration__c.Payment_Status__c, Registration__c.Name from Registration__c where Opportunity_del__c ='" + opp + "'" ); 

 var reg = [ ]; 
 var rstat = [ ]; 
 var pstat = [ ]; 
 var paystat1 = "ignore"; // set the default action for payment status 
 var regstat1 = "ignore"; // set the default action for registration status 



 //Figure out how many Registrations there are 
 var records = qr.getArray("records"); 
 var length = records.length 

 //Build an array of registration ID's and status 
 for (var i = 0;i<length;i++) { 
 reg[i] = records[i].get("Id"); 
 rstat[i] = records[i].get("Workshop_Cancelled__c"); 
 } 

 //Build a message to display the Id's 
 //var message = "The Reg's for Opportunity " + opp + " are: "; 

 //for (var i = 0;i<length;i++) { 
 //message = message + " " + reg[i] + " " + rstat[i]; 
 //} 

 //Display the message 
 //alert(message); 

 //Update the Stage of the Opportunity to show Closed - Won 
 var _Opportunity = new sforce.SObject("Opportunity"); //create an sObject for an object - here we are using opportunity but it could be anything 
 _Opportunity.Id = opp; //id should be gathered from a query or something earlier in the script - you'll need the id of the record you want to update though 
 _Opportunity.StageName = "Closed Won"; //you can hard code a value or pass something dynamically (can be any field) - here we are hard coding an update to the opportunity stage 
 var updateOpportunity= sforce.connection.update([_Opportunity]); //actually perform the update to the record 

 //check for success 
 if (updateOpportunity[0].getBoolean("success")) { //check that the update was successful 
 alert("Updated account: "+updateOpportunity[0].id); //alert success notification 
 } else { //otherwise unsuccessful 
 alert("API error: "+updateOpportunity[0]); //alert response from update attempt 
 } 

 if (length > 0) { 
 //Update each of the registrations to update Pending to Attended and ignore the other statuses 
 var _Registration = new sforce.SObject("Registration__c"); //create an sObject for an object - here we are using opportunity but it could be anything 
 var regstat; 

 for (var i = 0;i<length;i++) {//process each registration 
 // get the values from the current registration record 
 _Registration.Id = reg[i]; // get the record id for the update 

 //regstat = rstat[i]; // get the value of Registration status for the current registration 
 _Registration.regstat__c = rstat[i]; // store the initial registration status for update to track what happened 

 regstat1 = "ignore"; // reset the default action each pass 

 //Build a message to display the Id's 
 //var message = "The values for the reg are: \n"; 
 //message = message + " " + reg[i] + " " + rstat[i] + "\n"; 
 //Display the message 
 //alert(message); 

 if (rstat[i] == "Pending"){ // If the registration status is Pending , set to process 
 regstat1 = "process"; 
 _Registration.Workshop_Cancelled__c="Attended"; 
 } 
 _Registration.regstat1__c = regstat1; // Update the holder to show value after test 

 var updateRegistration= sforce.connection.update([_Registration]); //actually perform the update to the record 
 } 

 //check for success 
 if (updateRegistration[0].getBoolean("success")) { //check that the update was successful 
 alert("Updated registration: "+updateRegistration[0].id); //alert success notification 
 } else { //otherwise unsuccessful 
 alert("API error: "+updateRegistration[0]); //alert response from update attempt 
 } 
 } 
 alert("The process has completed"); 
 parent.location.href = url; //refresh the page 
}

If the Registration status is Pending, it should be changed to Attended. There is one registration in the 7 that has a status of Cancelled. The values that get stored back show that it should be ignored, but it is being changed to Attended.

Note... the registration status field is Workshop_Cancelled__c

I also wondered if there is a way to put this in an array and then post all seven updates back at once, as I believe I am handling them one at a time... could this be part of the problem?

Thanks,

...Dave