如果未选择单选按钮，则返回错误-PHP

Question

I've searched through a lot of previously asked questions about php and radio buttons but I haven't yet found something helping in my situation. I'm building a quiz for a server-side scripting class. I'm stuck on the actual quiz part. I want an error message to echo if the user does NOT select an answer to a question. Instead when I hit the submit button without selecting any options, I'm automatically redirected to the results page. How do I correct my code so that the user is given the error message if they hit submit without answering all of the questions? Below is the current code i've written out in an attempt to check the radio buttons and next steps.

<div id="question5"> <!-- each quiz question gets this set up -->
<h2 id="question5_error">WAIT! You did not pick an answer to this question!</h2>
<p>5. What creature pulls the Hogwarts carriages?<br>
<input type="radio" name="creature" value="Cornish Pixies" <?php if (isset($_SESSION["creature"]) && $_SESSION["creature"]="Cornish Pixies"){ echo"checked";} ?> > Cornish Pixies<br> <!-- php code checks to see if radio button has been selected-->
<input type="radio" name="creature" value="Clydesdales" <?php if (isset($_SESSION["creature"]) && $_SESSION["creature"]="Clydesdales"){ echo"checked";} ?> > Clydesdales<br>
<input type="radio" name="creature" value="Hippogriffs" <?php if (isset($_SESSION["creature"]) && $_SESSION["creature"]="Hippogriffs"){ echo"checked";} ?> > Hippogriffs<br>
<input type="radio" name="creature" value="Thestrals" <?php if (isset($_SESSION["creature"]) && $_SESSION["creature"]="Thestrals"){ echo"checked";} ?> > Thestrals<br>

<input type="hidden" name="sent" value="sent" onclick="Project1_Page2.php">
<input type="submit" name="goresults" value="Get Results?">|<input type="reset" name="resetquiz" value="Reset Quiz.">
</form> 
</article>
<?php
if(isset($_GET["sent"])){
echo "<script type = 'javascript'>";
if(!isset($_GET["question1"])){ // QUIZ QUESTION 1 CHECK
       $_SESSION["author"]=$_GET["author"];
    }
    else{
        echo "document.getElementById('question1').style.backgroundColor = '#ffcccc';
        document.getElementById('question1_error').style.display = 'block';";
    }
if(!isset($_GET["question2"])){ // QUIZ QUESTION 2 CHECK
    $_SESSION["godfather"]=$_GET["godfather"];
    }
    else{
        echo"document.getElementById('question2').style.backgroundColor = '#ffcccc';
        document.getElementById('question2_error').style.display = 'block';";
    }
if(!isset($_GET["question3"])){ // QUIZ QUESTION 3 CHECK
    $_SESSION["prison"]=$_GET["prison"];
    }
     else
    {
        echo"document.getElementById('question3').style.backgroundColor = '#ffcccc';
        document.getElementById('question3_error').style.display = 'block';";
    }   
if(!isset($_GET["question4"])){ // QUIZ QUESTION 4 CHECK
    $_SESSION["badguy"]=$_GET["badguy"];
    }
    else
    {
        echo"document.getElementById('question4').style.backgroundColor = '#ffcccc';
        document.getElementById('question4_error').style.display = 'block';";
    }
if(!isset($_GET["question5"])){ // QUIZ QUESTION 5 CHECK
    $_SESSION["creature"]=$_GET["creature"];
    }
    else
    {
        echo"document.getElementById('question5').style.backgroundColor = '#ffcccc';
        document.getElementById('question5_error').style.display = 'block';";
    }
echo "</script>";
}
?>

Answer 1

First of all if you are using radios you have set their attribute name to one like

<form method="post">
    <input name="question" value="1" />
    <input name="question" value="2" />
    <input name="question" value="3" />
    <input name="question" value="4" />
</form>

in this way you set your logic statement like so.

    if(isset($_POST['question'])){

    //here you put the the right answer based on the user what he/she chose.


    }

I suggest you to use POST is secured. If you are using GET the values of radio will appear on the url. I hope this will help.

Peace

Answer 2

Without seeing your HTML, it's hard to tell but here are some suggestions

in your form tag, remove "Action" attribute

<form method="post/get" >

then create a variable

$haserror = false;

and I'm not sure what are you trying to achieve here, but change the code like this

if(!isset($_GET["question1"])){ // QUIZ QUESTION 1 CHECK
       $_SESSION["author"]=$_GET["author"];
        echo "document.getElementById('question1').style.backgroundColor = '#ffcccc';
        document.getElementById('question1_error').style.display = 'block';";

$haserror = true; }

do the same for all checkboxes

then at the end do your if to show the result page

if(!$haserror)
{
    echo '<META http-equiv="refresh" content="0;URL=newpage.php">';

}

however I suggest to rewrite the whole thing, because you are approaching it in a wrong way