I'm not too sure how to do this. I need to validate email addresses using regex with something like this:

[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+(?:[A-Z]{2}|com|org|net|edu|gov|mil|biz|info|mobi|name|aero|asia|jobs|museum)

Then I need to run this in a jQuery function like this:

$j("#fld_emailaddress").live('change',function() { 
var emailaddress = $j("#fld_emailaddress").val();

// validation here? 

if(emailaddress){}

// end validation

$j.ajax({  
        type: "POST",  
         url: "../ff-admin/ff-register/ff-user-check.php",  
        data: "fld_emailaddress="+ emailaddress,  
        success: function(msg)
        { 
            if(msg == 'OK') { 
            $j("#fld_username").attr('disabled',false); 
            $j("#fld_password").attr('disabled',false); 
            $j("#cmd_register_submit").attr('disabled',false); 
            $j("#fld_emailaddress").removeClass('object_error'); // if necessary
            $j("#fld_emailaddress").addClass("object_ok");
            $j('#email_ac').html('&nbsp;<img src="img/cool.png" align="absmiddle"> <font color="Green"> Your email <strong>'+ emailaddress+'</strong> is OK.</font>  ');
            } else {  
            $j("#fld_username").attr('disabled',true); 
            $j("#fld_password").attr('disabled',true); 
            $j("#cmd_register_submit").attr('disabled',true);  
            $j("#fld_emailaddress").removeClass('object_ok'); // if necessary
            $j("#fld_emailaddress").addClass("object_error");
            $j('#email_ac').html(msg);
            }
        }
     });
});