Embedded Visualforce Page to Update Custom Field

Question

I am using an embedded Visualforce page as a custom button to update a custom field on my Opportunity record. The page saves fine and shows on my page layout, but when I click it, nothing happens. Does anyone see anything that could be causing this in my code below?

VF Page:

<apex:page standardController="Opportunity" >

<apex:includeScript value="/soap/ajax/26.0/connection.js"/>

<script type="text/javascript">
    function evp();
    {
        var opp = new sforce.SObject("Opportunity");
        opp.id = //set Record Id here, potentially get it from the URL ?id= param

        opp.Approval_Status__c = 'Sent to EVP';
        sforce.connection.update([opp]); 
        window.location.reload(); //to reload the window and show the updated values
    }
</script>

<apex:form>
<div style="text-align: center"><p/>

    <apex:commandButton Value="EVP Approval" onClick="evp();return false;"/>

</div>

</apex:form>

</apex:page>

Answer 1

There are three mistakes in your embedded visual force page

1. function evp(); remove semicolon from here.

2. You didn't assign opportunity Id to opp.id.

3. window.location.reload(); will not work here.

So I have fixed all these issues in new code :

<apex:page standardController="Opportunity" >

  <apex:includeScript value="/soap/ajax/26.0/connection.js"/>

  <script type="text/javascript">
     function evp()
     {
       var opp = new sforce.SObject("Opportunity");
       opp.id = "{!Opportunity.Id}";
       opp.Approval_Status__c = 'Sent to EVP';
       sforce.connection.update([opp]); 
       window.parent.location = '/' + opp.id;
     }
  </script>

  <apex:form >
     <div style="text-align: center"><p/>

         <apex:commandButton Value="EVP Approval" onClick="evp();return false;"/>

    </div>

  </apex:form>

</apex:page>

Answer 2

You apparently did not set the record ID.

opp.id = "{!Opportunity.Id}";

Every update requires either an External ID or a Salesforce ID. Also, you should probably handle the return value from sforce.connection.update to make sure no errors occurred; this would have let you know an error had happened.

try {
    sforce.connection.update([opp]);
catch(e) {
    alert("Error: "+e);
}