Send Hidden fields

add_filter(‘crmperks_salesforce_post’,’fn_add_data’);
function fn_add_data($post_data){
$post_data[] = ‘retURL=”https://peninsulaviewliving.com.au/”‘;
return $post_data;
}

Please have a look above the filter. is this correct? This filter put in my function.php file. Please confirm.
After adding this filter “retURL=”https://peninsulaviewliving.com.au/” field send to salesforce account automatically. Please confirm

<form action=”https://webto.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8&#8243; method=”POST”>

<input type=hidden name=”retURL” value=”https://peninsulaviewliving.com.au/”&gt;
<input type=”hidden” name=”Relationship_to_Customer__c” id=”Relationship_to_Customer__c” value=”Customer”>
<input type=hidden name=”Lead_Origin__c” value=”Tour Booking Page”>
<input type=hidden name=”RL_Website_Location__c” value=”Frankston South – Peninsula View Community”>

<label for=”first_name”>First Name *</label><input id=”first_name” maxlength=”40″ name=”first_name” size=”20″ type=”text” Required /><br>

<label for=”last_name”>Last Name *</label><input id=”last_name” maxlength=”80″ name=”last_name” size=”20″ type=”text” Required /><br>
</form>

you can see the above code of form where you can see the hidden fields.I want to send this hidden value also in the salesforce.