javascriptのラジオボタン検証フォーム

Question

ラジオボタンの検証を試みています（他の検証とともに）。ただし、ラジオボタンの検証に達すると、すべてがリセットされ、「フォームが送信されました」とは言わず、フォームの次の部分を検証しません。

function submit() { 
 
    alert("The form was submitted"); 
 
} 
 

 

 
function validate() { 
 
    if (document.myForm.user.value.length < 6) { 
 
    alert("Please enter a username that is at least 6 characters long"); 
 
    document.myForm.user.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.pass.value.length < 6) { 
 
    alert("Please enter a password that is at least 6 characters long."); 
 
    document.myForm.pass.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.pass.value != document.myForm.pass1.value) { 
 
    alert("Your passwords do not match! Please re-enter your password!"); 
 
    document.myForm.pass1.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.first.value == "") { 
 
    alert("Please provide your First name!"); 
 
    document.myForm.first.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.last.value == "") { 
 
    alert("Please provide your Last name!"); 
 
    document.myForm.last.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.address.value == "") { 
 
    alert("Please provide your Address!"); 
 
    document.myForm.address.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.city.value == "") { 
 
    alert("Please provide your City!"); 
 
    document.myForm.city.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.state.value == "") { 
 
    alert("Please provide your State!"); 
 
    document.myForm.state.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.zip.value == "" || 
 
    document.myForm.zip.value.length != 5) { 
 
    alert("Please provide a Zip code in the format #####."); 
 
    document.myForm.zip.focus(); 
 
    return false; 
 
    } 
 
    var zip = /^[0-9a]+$/; 
 
    if (!document.myForm.zip.value.match(zip)) { 
 
    alert("Please only enter numeric characters for the Zip code"); 
 
    document.myForm.zip.focus(); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.creditcard[0].checked = true) { 
 
    return true; 
 
    } else if (document.myForm.creditcard[1].checked == true) { 
 
    return true; 
 
    } else if (document.myform.creditcard[2].checked == true) { 
 
    return true; 
 
    } else { 
 
    alert("Please choose your credit card type!"); 
 
    return false; 
 
    } 
 

 
    if (document.myForm.creditno.value == "" || 
 
    document.myForm.creditno.value.length < 13) { 
 
    alert("Please provide a valid credit card number!"); 
 
    document.myForm.creditno.focus(); 
 
    return false; 
 
    } 
 

 
    if (!document.myForm.creditno.value.match(zip)) { 
 
    alert("Please provide a valid credit card number!"); 
 
    document.myForm.creditno.focus(); 
 
    return false; 
 
    } 
 

 
    alert("The form was submitted"); 
 
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
 
<p> 
 
    <form action="" name="myForm" onsubmit="return (validate())" ;> 
 
    Username: 
 
    <input name="user" type="text" size="25"> 
 
    <br>Password: 
 
    <input name="pass" type="password" size="20"> 
 
    <br>Confirm Password: 
 
    <input name="pass1" type="password" size="20"> 
 
    <br>First Name: 
 
    <input name="first" type="text" size="30"> 
 
    <br>Last Name: 
 
    <input name="last" type="text" size="30"> 
 
    <br> 
 
    <br>Address: 
 
    <input name="address" type="text" size="50"> 
 
    <br>City: 
 
    <input name="city" type="text" size="35"> 
 
    <br>State: 
 
    <input name="state" type="text" size="25"> 
 
    <br>Zip Code: 
 
    <input name="zip" type="text" size="5"> 
 
    <br> 
 
    <br>**Credit Card: 
 
    <br> 
 
    <input name="creditcard" type="radio">Visa 
 
    <br> 
 
    <input name="creditcard" type="radio">Mastercard 
 
    <br> 
 
    <input name="creditcard" type="radio">American Express 
 
    <br> 
 
    <br>** Credit Card #. 
 
    <input name="creditno" type="password" size="25"> 
 
    <br> 
 
    <br>We welcome your comments and feedback: 
 
    <br> 
 
    <textarea maxlength="100"></textarea> 
 
    <br> 
 
    <input type=submit value="Submit Query"> 
 
    <input type=reset> 
 

 
    </form> 
 

 
</p>

Answer 1

（document.myForm.creditcard [0]の場合の前に**どのようなものがあり.checkedをこの

chosen = ""; 
len = document.myForm.creditcard.length; 

for (i = 0; i <len; i++) { 
    if (document.myForm.creditcard[i].checked) { 
     chosen = document.myForm.creditcard[i].value 
    } 
} 

if (chosen == "") { 
    alert("Please choose your credit card type!"); 
    return false; 
}