Autofill fields based on the query string (using Google Analytics tracking variables in this example)

salesforce_w2l_field_value_querystring_multiple_example.php

<?php
// Autofill fields based on the query string (using Google Analytics tracking variables in this example)

add_filter( 'salesforce_w2l_field_value', 'salesforce_w2l_field_value_querystring_multiple_example', 10, 3 );

function salesforce_w2l_field_value_querystring_multiple_example( $val, $field, $form ){

    $form_id = 1; // form id to act upon
	
	if( $form != $form_id ){
		return $val;
	}
	
	// key = API Name of the field you want to autofill - you have to create these custom fields at Salesforce first!
	// val = Query string variable to grab - e.g. ?source=foo
	// Add lines as needed
	
	$map = array(
		'utm_source__c' => 'utm_source',
		'utm_medium__c' => 'utm_medium',
		'utm_campaign__c' => 'utm_campaign',
		'utm_term__c' => 'utm_term',
		'utm_content__c' => 'utm_content',
	);
	
	foreach( $map as $field_name => $qs_var ){
	    if( $field_name == $field ){
	        if( isset( $_GET[ $qs_var ] ) ){
	            return $_GET[ $qs_var ];
	        }
	    }    
    }

    return $val;

}