function is_valid_email(email) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   
   return reg.test(email);
}

function is_valid_zipcode(zipcode) {  
    var reg = /^([0-9]{5})$/;
    
    return reg.test(zipcode); 
}


function is_valid_phonenumber(phonenumber) {
    var trimmed = phonenumber.replace(/[^0-9]/g,'');
    if ( trimmed.length == 10 ) {
        return true;
    } else {
        return false;
    }
}

function is_valid_ssn(ssn) {
    var reg = /^([0-9]{3})-([0-9]{2})-([0-9]{4})$/;
    
    return reg.test(ssn);
}