如何在JavaScript中正确验证CAPTCHA？

Question

I'm in the middle of coding CAPTCHA in JavaScript, and I'm trying to get the validation for a contact form to work properly. I'm almost there, the form won't be submitted until the CAPTCHA text-field is entered, but the problem is I'm still getting an error message when I entered the CAPTCHA code correctly.

<script>
function ValidateContactForm()
{
var name = document.ContactForm.name;
var phone = document.ContactForm.phone;
var code = document.ContactForm.code;

    if (name.value == "")
{
    window.alert("Please enter your name.");
    name.focus();
    return false;
}

if (phone.value == "")
{
    window.alert("Please enter a valid phone number..");
    phone.focus();
    return false;
}

if (code.value == "")
{
    window.alert("Please enter the code as displayed on screen."); 
    code.focus();
    return false;
    }
    else if (code.value != "") 
{
        window.alert("Your code does not match. Please try again."); 
    code.focus();
    return false;
 }

else {
    return true;
}

return true;
}
</script>

Any help would be greatly appreciated. Thanks.

Answer 1

Check this lines, the problem is here:

if (code.value == "")
{
    window.alert("Please enter the code as displayed on screen."); 
    code.focus();
    return false;
}
else if (code.value != "") 
{
    window.alert("Your code does not match. Please try again."); 
    ^^^^^^^^^^^^^
    code.focus();
    ^^^^^^^^^^^^^
    return false;
    ^^^^^^^^^^^^^
 }
else {

    return true;
}

This code will return false every time.