js code

/* function to test the length       */
function testLength(value, length) {

    if(value.length == length) {

        return true;
    }
        return false;
}

/* check if the value passed is a real value */
function testNumber(value) {

    if(isNaN(value)){
        return false;
    }
        return true;
    }

/* check if the control's value is the correct length */
function validateControl(control, name, length){

    // the result of this function
    var result = false;
    // test the number
    if(testLength(control.value,length)){
        // test the number
        if(testNumber(control.value)){

            result = true;
        }
    }
            return result;
}

/* checks if a credit card is valid or not */
function validateCreditCard(value){

    value = value.split(" ").join(" ");
    // the result of the function
    var result = true;
    // the test for it being a #
    if(!testNumber(value)){

        console.log("Credit card details entered are not a number");
        return false;
    }
    if(!(Number(value.charAt(0))== 3 || Number(value.charAt(0)) == 4 || Number(value.charAt(0)) == 5 || Number(value.charAt(0)) == 6)){

    Console.log("Invalid Credit card starting with" + Number(value.charAt(0)));
    // if the credit card is invalid
    return false;
    }

    /* if the credit card is valid then check for the length of the digits */
    if(Number(value.charAt(0) == 3)) { // this is for the AmEx

        if(!testLength(value,15)){

            console.log("Invalid Credit Card");
            return false;
        }
        }
        else{
            if(!testLength(value,16)){

                console.log("Invalid Credit Card");
                return false;
            }
        }
        return result;
}

/* if the value is greater than today's date or not ) */
function validateDate(value){

    var todayDate = new Date().getDate();

    if(Number(value.split("-")[2])>todayDate){

        console.log("Wrong Date Selcected");
        return false;
    }
        // the date must be valid
        return true;
}

/* test that the email is in the correct format w/ RegEx */
function validateEmail(value){

    var RegEx = /\S+@\S+\.\S+/;
    return RegEx.test(value);
}

/* validate the form */
function validateForm()
{

    // we need to get all of the references of dom objects in vars
    var cvc = document.getElementByld("cvc");
    var zip = document.getElementByld("Zip");
    var cc = document.getElementByld("CreditCard");
    var date = document.getElementByld("Date");
    var state = document.querySelector("#State");
    var email = document.getElementByld("Email");

    // check all details entered in the form, is the cvc 3 digits and is the zip 5 digits.
    if (validateControl(cvc, "cvc", 3) && validateControl(zip, "Zip", 5) && validateCreditCard(cc.value) && validateDate(date.value) && validateEmail(email.value) && validateState(state.selectedIndex))
    {

        console.log("Payment Submitted");
        document.querySelector('.output').textContent = "Payment Sent";
        return true;
    }
        document.querySelector('.output').textContent = "Payment Failed";
        return false;
}

/* the state selected is checked if its valid */
function validateState(value){

    var state = document.getElementById("State");
    if(value != state.selectedIndex || state.selectedIndex == 0) {

        console.log("Please select the correct state");
        return false;
    }
        return true;
}