I have a custom buttom, that is called "Create Sales Order". I want it to update to Processing unless one of the below else if statements is valid. The issue is, my error message displays but then still changes the Stage to Processing. Can you help me understand what I'm missing to prevent this from happening? 

Thanks!


{!REQUIRESCRIPT("/soap/ajax/23.0/connection.js")} 

try { 
var url = parent.location.href; 
var updateRecords = []; 
var update_Opportunity = new sforce.SObject("Opportunity"); 
update_Opportunity.Id ="{!Opportunity.Id}"; 
update_Opportunity.StageName = "Processing"; 
updateRecords.push(update_Opportunity); 

result = sforce.connection.update(updateRecords); 

if ("{!Opportunity.Sales_Order__c}" == true) { 

alert("Your request to create an ERP sales order has already been submitted."); 

} 

else if ( !result[0].getBoolean("success") ) { 

var errors = result[0].errors; 
var errorMessages = errors.message; 
alert( errorMessages ); // display all validation errors 

} 
else if ("{!Opportunity.Account_Order_Ready__c}" == false) { 

alert("The related account is not order ready. Your sales order request will not be processed."); 
} 

else if ("{!Opportunity.StageName}" == 'Approved Prebook') { 

alert("This opportunity must be approved by your inside rep to proceed"); 

} 

else { 
alert("Your request has been submitted") 
} 
parent.location.href = url; 

} catch (e) { 
alert 
}