PHP: why variable does not get reloaded after a Submit?

Question

Here is a code that I've made:

<form method="post" action="test.php">
<input type="text" name="name" placeholder="name"/><br />
<input type="submit" value="Validate" />
</form>
<?php
$sum=0;
if(isset($_POST['name'])){
   $sum+=1;
}
echo "sum = $sum";
?>

When I enter some text in the form and click Validate, the page display sum=1, but after this, when I enter nothing in the form and click Validate, the page STILL displays sum=1.

Why does the variable $sum is not reloaded between the two Validate ? Is there a way to escape it ?

Thanks

Because you are setting it hard to 0 a few lines before. The script is always executed complete and not starting with your if-statement — frlan
– frlan, Commented Dec 17, 2016 at 11:22

Kalaivani M · Accepted Answer · 2016-12-17 11:26:32Z

1

This will solve the issue

<?php
$sum=0;
if(isset($_POST['name']) && $_POST['name'] != ''){
    $sum+=1;
}
echo "sum = $sum";
?>

edited Dec 17, 2016 at 11:26

Kalaivani M

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answered Dec 17, 2016 at 11:22

Akshay

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3 Comments

frlan Over a year ago

I think it will not.

frlan Over a year ago

I have to revert myself. Understood the question wrong

Akshay Over a year ago

Not an issue. It happens :p

Amin NAIRI · Accepted Answer · 2016-12-17 12:43:46Z

1

This is because isset() checks for the existence of the $_POST variable. In your case, the $_POST variable exists and has an empty string value.

Your code will work if you change isset() to !empty() like so;

<form method="post" action="test.php">

<input type="text" name="name" placeholder="name"/><br />


<input type="submit" value="Validate" />
</form>


<?php

$sum=0;

if(!empty($_POST['name'])){
    $sum+=1;
}

echo "sum = $sum";

?>

More about the empty() function here.

edited Dec 17, 2016 at 12:43

Amin NAIRI

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answered Dec 17, 2016 at 11:22

tkounenis

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Comments

Amin NAIRI · Accepted Answer · 2016-12-17 20:44:22Z

Another way would be to check the request that your client has made on your page. So that if it is a simple refresh (not with a form refresh), it is a GET request and so, the variable should not be incremented and if the form has been sent, then you can do whatever you want such as incrementing the data.

So if the client is sending the form with an input text filled, then you can increment the value. In all other cases, the value should remain a zero.

<form method="post" action="test.php">

    <input type="text" name="name" placeholder="name"/><br />
    <input type="submit" value="Validate" />

</form>

<?php

    $sum=0;

    if ($_SERVER['REQUEST_METHOD'] == 'POST' && isset($_POST['name']) && !empty($_POST['name']))
    {
        $sum++; /* strictly equivalent to: $sum += 1; */
    }

?>

<samp>sum = <?php echo $sum; ?></samp>

Kalaivani M · Accepted Answer · 2016-12-17 11:22:36Z

0

Try this

<form method="post" action="test.php">
<input type="text" name="name" placeholder="name"/><br />
<input type="submit" name="submit" value="Validate" />
</form>
<?php
$sum=0;
if(isset($_POST['submit'])){
   $sum+=1;
}
echo "sum = $sum";
?>

answered Dec 17, 2016 at 11:22

Kalaivani M

1,31016 silver badges29 bronze badges

Comments

gmcoding · Accepted Answer · 2016-12-17 11:24:20Z

0

You can try below:

if(isset($_POST['name']) && strlen($_POST['name'])>0){
$sum+=1;

answered Dec 17, 2016 at 11:24

gmcoding

2392 silver badges8 bronze badges

Comments

CodeSponge · Accepted Answer · 2016-12-17 11:39:12Z

0

You have the code appending 1 to variable $sum but your if statement is based on the name field being passed. Not if the name field has any data in it. So... you have made your code add 1 as long as name field is passed, regardless if it has text input or not.

Also, you should reassign the varible to reset it. += should just be =

      <form method="post" action="test.php">


   //----------------------------- add empty value to input ------------
    <input type="text" name="name" value="" placeholder="name"/><br />


    <input type="submit" value="Validate" />
    </form>


    <?php

    $sum=0;

    if(isset($_POST['name'])){
        $sum=1;
    }

    echo "sum = $sum";

    ?>

edited Dec 17, 2016 at 11:39

answered Dec 17, 2016 at 11:33

CodeSponge

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