This seems like it should be straightforward, but it doesn't work.  I don't receive any errors, but nothing happens.

The Move__c object is on the detail side of a Master-Detail relationship with Client__c.

I'm trying to use the button to grab field values from Move__c, and pass those values into fields on Client__c.

Am I trying to do something that won't work?

{!REQUIRESCRIPT("/soap/ajax/20.0/connection.js")} 

var connection = sforce.connection; 

var url = parent.location.href; //string for the URL of the current page 
var clientMoved = "{!Move__c.ClientId__c}"; 

var moveToStreet = "{!Move__c.Move_To_Street__c}"; 
var moveToCity = "{!Move__c.Move_To_City__c}"; 
var moveToState = "{!Move__c.Move_To_State_Province__c}"; 
var moveToZip = "{!Move__c.Move_To_Zip_Postal_Code__c}"; 
var moveToCountry = "{!Move__c.Move_To_Country__c}"; 
var moveToProperty = "{!Move__c.Property__c}";

var client= new sforce.SObject("Client__c"); 
client.Id = clientMoved; 

client.Mailing_Street__c = moveToStreet; 
client.Mailing_City__c = moveToCity; 
client.Mailing_State__c = moveToState; 
client.Mailing_Zip_Code__c = moveToZip; 
client.Mailing_Country__c = moveToCountry; 

client.Shipping_Street__c = moveToStreet; 
client.Shipping_City__c = moveToCity; 
client.Shipping_State__c = moveToState; 
client.Shipping_Zip_Code__c = moveToZip; 
client.Shipping_Country__c = moveToCountry; 

client.Property__c = moveToProperty;

connection.update([client]); 
parent.location.href = url; //refresh the page