How to Extend this jQuery code to validate empty input text fields

I am currently using the below code to check for a club code thats being entered into a input text field. I am checking it against a csv file, everything works great,

I would like to add some input validations for the 2 input fields, basically if they are left empty, just want to display a message saying fields are required and cannot be left empty.  I am already showing one more error when the club code is not correct,

I would like to extend that and show the above message.

So basically here are some of the error messages:

1) if the clubcode is left empty show message saying clubcode can't be empty
2) if the zipcode is left empty show message saying zipcode can't be empty
3) Clubcode can only be 8 characters and alphanumeric
4) zipcode can only accept zipcode ( basically zipcode 10 number format)
and finally the other existing error message.

I am not looking for the complete solution, just want to know how to extend my code  I have, even if someone can show me 1 and 3 I would highly appreciate it.

here is what I have so far which works.

                <h2>Testing Club Code</h2>
				 <p>Please Enter your Code below and click the Verify Code Button.</p><br /><br />
                 <div style="display:block;">
				 <form id="verify" action="TestCode.html" method="post" autocomplete="off">
				    <div class="form_row">
					 <span style="color:#A0000A;">* Required</span><br />
				  	 <label class="required"><em>*</em>Club Code:</label>
                     <input type="text" name="club1-code" id="club1-code" value="" /><br />
                     <label class="required"><em>*</em>Zip Code:</label>
                     <input type="text" name="zip-code" id="zip-code" value="" />
					  </div>
				   <div class="form_row">
				      <input type="submit" value="Verify Ski Code" name="verify-code" id="verify-code" class="button" />
                    </div>
                    </form>
                    </div>
                    <div id="ClubRegister">
		              <a class="Button" href="/TestResults.html"><span>Click to View Your Test Results</span></a>
					</div>
                    <div id="ClubError">
					  <div class="errormessage">Verification Failed. Please Enter a Valid club Code.</div>
					</div>
                    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>

<script type="text/javascript">
var lines;

$(document).ready(function () {
    $("#ClubRegister").hide();
    $("#ClubError").hide();
	
	$.get("/clubcodes.csv", function(data) {
        $("#verify-code").data("testcodes", data.split(',')).click(function(e) {
            e.preventDefault();
            if ($.inArray($("input[name=club1-code]").val(), $(this).data("testcodes"))>=0) {
                $("#ClubRegister").show();
                $("#ClubError").hide();
				
            } else {
                $("#ClubError").show();
                $("#ClubRegister").hide();
            }
        });
    }, "text");

});

</script>     

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