var mailAppsOpen;

jQuery(document).ready (function() {    
    jQuery("#AppMailPDFLink").click(function() {
        if (!mailAppsOpen) {
            jQuery("#appMail").show(500);
            mailAppsOpen = true;
            jQuery("#AppMailPDFLink").html("Hide mail-in applications")
        } else {
             jQuery("#appMail").hide(500);
            mailAppsOpen = false;
            jQuery("#AppMailPDFLink").html("Display mail-in applications")
        }
    });
});