Hello awesome developers!

I am stuck here, and I will be up front I am prety new to the apex extension for VF pages.  

I am attempting to as a record is closed, send an email from a workflow with an url to a VF page for an user to fill out a brief survey.  I am attempting to place a parameter in the URL of the closing records ID to then pre populate the lookup field on the VF page with the ID of the closing record that is sending the survey needed email. 

I have the following VF page built and extension, however when the page is loaded, the lookup field on the VF page is not being populated.  Any ideas on what I did incorrectly and or ideas on how to make this work?  

I appreciate any input,

PS...once this is working, since I am new to the extension building, any insights on building a test class for the extension?

Shawn

VF Page:
 

<apex:page standardController="Salesforce_Support_Survey__c" sidebar="false" showHeader="false" extensions="SalesforceSupportSurveyController" docType="html-5.0">
   
    <style>
    html, body, p { 
        font-family: "ProximaNovaSoft-Regular", Calibri, 
            "Gill Sans", "Gill Sans MT", Candara, Segoe, 
            "Segoe UI", Arial, sans-serif; 
        font-size: 110%;
    }
    input { font-size: 95%; }
	</style>
    
    <apex:form >
        <apex:pageBlock title="Thank you for taking our short survey!" mode="edit">
            <apex:pageBlockButtons >
                <apex:commandButton action="{!save}" value="Submit Survey"/>
            </apex:pageBlockButtons>
            <apex:pageBlockSection title="Survey Questions:" columns="2">
                <apex:outputField value="{!Salesforce_Support_Survey__c.X1_Timliness__c}"/>
                <apex:inputField value="{!Salesforce_Support_Survey__c.X1_Answer__c}"/>
                <apex:outputField value="{!Salesforce_Support_Survey__c.X2_Satisfaction__c}"/>
                <apex:inputField value="{!Salesforce_Support_Survey__c.X2_Answer__c}"/>
                <apex:outputField value="{!Salesforce_Support_Survey__c.X3_Submission_process__c}"/>
                <apex:inputField value="{!Salesforce_Support_Survey__c.X3_Answer__c}"/>
                <apex:outputField value="{!Salesforce_Support_Survey__c.X4_Enhancement_Ideas__c}"/>
                <apex:inputField value="{!Salesforce_Support_Survey__c.X4_Answer__c}"/>
                <apex:outputField value="{!Salesforce_Support_Survey__c.X5_Additional_Comments__c}"/>
                <apex:inputField value="{!Salesforce_Support_Survey__c.X5_Answer__c}"/>
                <apex:inputField value="{!Salesforce_Support_Survey__c.Issue__c}"/>
                 <script>
          			document.getElementById('{!$Component.dynFieldName}_lkid').value = '{!IssueId}';
          			document.getElementById('{!$Component.dynFieldName}').value = '{!IssueName}';
      			</script>
            </apex:pageBlockSection>
        </apex:pageBlock>
    </apex:form>
</apex:page>

Extension:
 

public class SalesforceSupportSurveyController
{
    public string IssueId
    {    get;set;    }

    public string IssueName
    {    get;set;    }
    
    public SalesforceSupportSurveyController(ApexPages.StandardController ctlr)
    {
        IssueId = System.currentPageReference().getParameters().get('lookupVal');
        IssueName = [select Name from SFDC_Issue__c where Id =: IssueId].Name;
    }
}