Proper PHP input for HTML form

Question

Currently getting an 'Unidentified Index' error for my PHP file.

I created a form on an HTML that requires users to enter info into a textbox. It's a basic calculation, like 5X3, so the user must enter '15'. I then need to use PHP as well as an if-else statement to determine if the user correctly entered the right number. But I believe that I have not properly set up my PHP file. This is my first time using PHP, so I'm not entirely sure what other alternatives to using. I have pretty much just structured my PHP file off examples from our lecture notes. Have I properly set everything up?

//HTML form code
<label for="Question 3">Question Three: <strong>2 X 9</strong></label><br>
<input type="text" id="Q3" name="Q3" placeholder="Type Answer Here"><br>

//PHP code for corresponding label
$Q3 = $_POST['Q3'];

//if statement regarding a particular question
if ($Q3 == "18")
  {
    echo "Well done, that's Correct!";
  }
  else
  {
    echo "Sorry, that's incorrect.";
  }

Well done, that's correct! //if user inputs correct answer actual results:

Notice: Undefined index: Q1 in /Applications/XAMPP/xamppfiles/htdocs/CIT273/timetable.php on line 6

You have to use if(isset($_POST['Q3'])) { } and put your all php code inside this. — user11988937
– user11988937, Commented Oct 16, 2019 at 5:29

Shubham Narvekar · Accepted Answer · 2019-10-16 05:43:01Z

3

You first need to wrap ur input in a form tag with a post action

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">  
  <label for="Question 3">Question Three: <strong>2 X 9</strong></label>
  <input type="text" id="Q3" name="Q3" placeholder="Type Answer Here">
  <input type="submit" name="submit" value="Submit">  
</form>

<?php
        //if statement regarding a particular question
        if ($_POST['Q3'] == "18") {
            echo "That's Correct!";
        } else {
            echo "That's incorrect.";
        }
?>

answered Oct 16, 2019 at 5:43

Shubham Narvekar

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1 Comment

GraysonG Over a year ago

I have a form method above, I just decided to choose 'Q3' as my example. Assumed people willing to help weren't going to waste their time glancing over pretty much a repetitive program.

Krupal Panchal · Accepted Answer · 2019-10-16 05:32:16Z

0

Try This one.

<form method="post">
    <label for="Question 3">Question Three: <strong>2 X 9</strong></label><br>
    <input type="text" id="Q3" name="Q3" placeholder="Type Answer Here"><br>
</form>

<?php
    if($_SERVER['REQUEST_METHOD'] == 'POST') {
        $Q3 = $_POST['Q3'];

        //if statement regarding a particular question
        if ($Q3 == "18") {
            echo "Well done, that's Correct!";
        } else {
            echo "Sorry, that's incorrect.";
        }
    }
?>

answered Oct 16, 2019 at 5:32

Krupal Panchal

1,5452 gold badges15 silver badges27 bronze badges

3 Comments

GraysonG Over a year ago

awesome. every time I tried to launch 'Submit' my form, I have been having extreme difficulty. I wasn't sure if this was because of how I set my PHP file up or what. But still trying to figure that one out!!

GraysonG Over a year ago

so, i still haven't been able to figure out my path yet. so when I load this into my server. should I be getting a blank page? Since I haven't inputted anything for my Q3?

Krupal Panchal Over a year ago

You can put this code directly in your <body> tag. and it will work good.

Viszman · Accepted Answer · 2019-10-16 05:34:26Z

0

you can resolve that in 2 ways

as @Robin Singh pointed //PHP code for corresponding label

if(!isset($_POST['Q3'])) {
    $Q3 = null;
}

OR

$Q3 = $_POST['Q3'] ?? null

that way you will have null in $Q3 when user don't input anything

answered Oct 16, 2019 at 5:34

Viszman

1,3981 gold badge19 silver badges49 bronze badges

2 Comments

GraysonG Over a year ago

ok awesome. Now this is a bit off-topic of my above question. But I created my PHP file externally from my html file. Would incorrectly setting the path obstruct my outcome? I have literally spent hours today trying to correctly set this up. I downloaded XAMPP for my server but for some reason just can't get my intended outcomes to display, or in fact even load once I hit my 'submit' button on my html form. Any idea how to fix this? I'm doing this on my personal Mac. If not, no biggie!

Viszman Over a year ago

there is always room for mistake :)

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