Validate dynamically named radio buttons using javascript

Question

I have been trawling through various examples of radio buttons validation and grasp the concept but no examples seem to fit my situation. I have queried my database which has 4 options and for each option I have generated an associated radio button as below:

<?php foreach($options as $option){ ?>

<p><input type="radio" name="ID<?php echo $row['id']; ?>" value="<?php echo $option; ?>"><?php echo $option; ?></p>

<?php } ?>

So this basically generates 4 radio buttons per row called from the database. This appears in the source as:

<form method="POST" action="Result.php">
    <p>1.  Question </p>
        <p><input type="radio" name="ID1" value="answer1">answer1</p>
        <p><input type="radio" name="ID1" value="answer2">answer2</p>
        <p><input type="radio" name="ID1" value="answer3">answer3</p>
        <p><input type="radio" name="ID1" value="answer4">answer4</p>
    <p>2.  Question 2</p>   
        <p><input type="radio" name="ID2" value="answer1">answer1</p>
        <p><input type="radio" name="ID2" value="answer2">answer2</p>
        <p><input type="radio" name="ID2" value="answer3">answer3</p>
        <p><input type="radio" name="ID2" value="answer4">answer4</p> 
    <input type="submit" name="submit" value="Submit!">          
</form>

etc etc.

The names of these radio buttons are partially generated by php, how can I use javascript with an associated alert to check 1 of the radio buttons from each question has been checked prior to submitting the form the questions are populated within?

Or maybe even just how can I achieve this with php ISSET?

In your result.php, isset($_POST['ID1']) will return true if one of these radio buttons from the first question was checked. Then $_POST['ID1'] will hold the value of either answer1, answer2 and so on. — Eddi
– Eddi, Commented Feb 9, 2017 at 15:31
Eddi, thank you your reply, I understand this would happen within the results.php but my question was how could I verify the form within the same page prior to submitting the form on to results.php sorry for the confusion — Kieran
– Kieran, Commented Feb 9, 2017 at 15:37

Eddi · Accepted Answer · 2017-02-09 15:46:43Z

2

Using just JavaScript to verify whether a radio button within a radio group is checked:

function radiogroupSelected(name){
    var inputArr = document.getElementsByName(name);
    for(var i = 0; i < inputArr.length; i++){
        if(inputArr[0].checked){
            return true;
        }
    }

    return false;
}

Now you can call this function like radiogroupSelected('ID1') to determine if one of the inputs was selected.

answered Feb 9, 2017 at 15:46

Eddi

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1 Comment

Kieran Over a year ago

Thank you for your help, im used this concept and expanded it for each ID. Appreciate the answer thank you!

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