// Iterate through the fields and display them.
	foreach($fieldSet as $field):
		//Check ACL
	    if ((method_exists($field, 'canView')) && !$field->canView())
	    	continue;
	    // If the field is hidden, only use the input.
	    if ($field->hidden):
	        echo $field->input;
	    else:
	    ?>
	    <dt>
	        <?php echo $field->label; ?>
	    </dt>
	    <dd<?php echo ($field->type == 'Editor' || $field->type == 'Textarea') ? ' style="clear: both; margin: 0;"' : ''?>>
	        <?php echo $field->input ?>
	    </dd>
	    <?php
	    endif;
	endforeach;

// set some vars for the vale you need to concatenation into your membership no
var stateVal = jQuery("jform_{id-of-your-state-field}").val();
var companyCodeVal = jQuery("jform_{id-of-your-company-code-field}").val();
var membershipTypeVal = jQuery("jform_{id-of-your-membership-type-field}").val();

// concatenate them - change the "-" delimiter to whatever you want
var membershipNoVal = stateVal + "-" + companyCodeVal + "-" + membershipTypeVal;

//set the membership number fld to your calculated value
 jQuery("jform_{id-of-your-membership-number-field}").val(membershipNoVal);

<script type="text/javascript">
  // Script to Auto Generate the Membership Number
  jQuery(document).ready(function($) { 
	// Set input field change events to trigger the update membership number
	$("#jform_company_code").on("change",updateMemNum);
	$("input[name='jform[membership_type_id]']").on("change",updateMemNum);
	$("input[name='jform[state_id]']").on("change",updateMemNum);
	
	function updateMemNum() {	
	  // Get the State Radio Value
	  var stateId = $('input:radio[name="jform[state_id]"]:checked').prop("id");
	  var stateLabel = $('label[for='+stateId+']').text();
				
	  //Get the Company Code
	  var companyCodeVal = $("#jform_company_code").val();
				
	  // Get the Membership Type Radio Value
	  var membershipTypeId = $('input:radio[name="jform[membership_type_id]"]:checked').prop("id");
	  var membershipTypeLabel = $('label[for='+membershipTypeId+']').text();
				
	  // concatenate to make the membership No
	  var membershipNoVal = stateLabel + "-" + companyCodeVal + "-" + membershipTypeLabel;
				
	 //set the membership No
	 $("#jform_membership_number").val(membershipNoVal);	   		   
	} //end function
});//end document.ready
</script>

// JS
var seqNo = 0; // or whatever you want to start from

//Then, increment it
seqNo ++;

protected function prepareQuery(&$query, $pk)

public function save($data){	
	//Do what you want before. Work with $data
	
	// The original call to the Parent Save Script
	$result = parent::save($data);
	
	//Do what you want after. Read and work on $result
	
	return $result;
}

public function save($data){	
	//Do what you want before. Work with $data
	
	// The original call to the Parent Save Script
	$result = parent::save($data);
	
	//Do what you want after. Read and work on $result
	
	return $result;
}

echo "<pre>data:". print_r($data,true)."</pre>";		//debug