Currently, when a button is clicked to upload file , the object record is created first - then through actionFunction oncomplete, the document is submitted to amazon S3. I need this to be reversed... submit completion first - then create the file. I've tried to play with jQuery because research indicated it might be applicable to this problem. But...after 5 hours of being unsuccessful (i'm completely new to javascript and jQuery, and was hoping for some guidance here) - i'm looking for some advice.

This is the relevant code, untouched (working as is). I can post my jQuery edits if anyone requests, but i'm not sure if it's even the viable option and i'm sure something is wrong there as well.

Is there a javascript function (i've googled, and no examples ive found help) that invokes a method in salesforce, AFTER the document submission? not onsubmit, must be after a successful "upload"

   <apex:pageMessages id="pageErrors"></apex:pageMessages>
   
    <form name="s3Form" action="https://s3.amazonaws.com/mycompanybucket" method="post" enctype="multipart/form-data">   
        
        <input type="hidden" name="key"/> 
        <input type="hidden" name="AWSAccessKeyId" value="{!key}"/> 
        <input type="hidden" name="policy" value="{!policy}"/>
        <input type="hidden" name="signature" value="{!signedPolicy}"/> 
        <input type="hidden" name="acl" value="private"/> 
        <input type="hidden" name="x-amz-meta-FileId" value="{!File__c.id}"/>
        <input type="hidden" name="x-amz-meta-OrderId" value="{!OrderId}"/>
        <input type="hidden" name="x-amz-meta-CustomerId" value="{!CustomerId}"/>     
        <input type="hidden" name="success_action_redirect" value="{!serverUrl}{!OrderId}"/>           
        
        <apex:pageBlock title="New File Upload" mode="maindetail" tabStyle="File__c">
        
            <apex:pageBlockSection title="File Information" columns="2" collapsible="false" showHeader="false"> 
                                                                       
                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Select File" for="selectFile"/>            
                    <input id="selectedFile" type="file" size="25" name="file" onChange="setFileName(this.value)"/>                
                </apex:pageBlockSectionItem>    

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Select File" for="fType"/>                            
                    <select id="fType" onChange="setFileType(this.value)">
                        <option value="--None--">--None--</option>
                        <option value="Valuation">Valuation</option>
                        <option value="Data Sheet">Data Sheet</option>
                        <option value="Invoice">Invoice</option>
                        <option value="Review">Review</option>
                        <option value="Other">Other</option>
                    </select>                          
                </apex:pageBlockSectionItem>                                        
                           
            </apex:pageBlockSection>

            <apex:pageBlockButtons location="bottom">
                <input class="btn" type="button" value="Upload File" onClick="checkFile();return false;"/>                
                <input class="btn" type="button" value="Cancel" onClick="cancelFile();return false;"/>
                <input class="btn" type="button" value="Complete Order" onClick="completeFile();return false;"/>
            </apex:pageBlockButtons>          

        </apex:pageBlock>
       
    </form> 
    
     <apex:form id="sfForm">
     
        <apex:inputHidden id="hiddenServerURL"  value="{!serverURL}"/>
        <apex:inputHidden id="fileName" value="{!fileName}"/>
        <apex:inputHidden id="contentType" value="{!contentType}"/>
        <apex:inputHidden id="fileType" value="{!fileType}"/>
        <apex:actionFunction name="insertFile" action="{!insertFile}" oncomplete="submitFile();return false;"/>
        <apex:actionFunction name="completeOrder" action="{!completeOrder}"/>

        
        <script type="text/javascript">
        var sendFile = false;
        document.getElementById('{!$Component.hiddenServerURL}').value = '{!$Api.Enterprise_Server_URL_140}';       
        function setFileName(file) {
            var f = file.replace(/\\/g, "");
            f = f.replace(/C\:fakepath/g, ""); <!--Required for IE8-->
            document.s3Form.key.value = "{!CustomerName}/{!OrderName}/" + f;
            document.getElementById('{!$Component.fileName}').value = f;
            suffix = f.lastIndexOf(".") + 1;
            contentType = f.slice(suffix);
            document.getElementById('{!$Component.contentType}').value = contentType;
        }
        function setFileType(type) {
            document.getElementById('{!$Component.fileType}').value = type;
        }
        function checkFile() {
            if (document.s3Form.file.value=="") {
                alert("Please, select a file.");
                return false;
            } 
            else if (document.s3Form.fType.value=="--None--") {
                alert("Please, select a file type.");
                return false;
            }
            else {     
            	alert("Uploading...Please click OK and wait for page to refresh.");        
              	insertFile();
               	sendFile = true;
            }
        }
        function submitFile() {
            if(sendFile = false) {
            return false;
            }
            else {
            document.s3Form.submit();
            }
        } 


insertFile() Method on extension:

//SF File insert on an object (passed from page)
    public PageReference insertFile() {
        this.file.Name = fileName;
        this.file.Type__c = fileType;
        this.file.Content__c = contentType;
        insert this.file;
        return null;
    }