Help with converter script

[dtommy79]

Hi,

I created a simple script that converts miles to kilometer. I added it to an HTML file and it works fine, but when I load the page (and there is nothing to convert) it gives me an error:

 

 

Notice: Undefined index: mile in F:\wamp64\www\exchange\convert.php on line 130

 

So basically what I want is to display nothing on page load or if there is nothing in the input field. Here is my code:

<h3 class="section-heading">Convert Miles to Kilometer II.</h3>
                            <hr class="primary">
                            <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>" style="margin-top: 20px;">

                                <p>Add Miles:
                                    <input type="text" class="form-control" placeholder="miles" name="mile" size="2" />  
                                </p>
                                <p>
                                    <input type="submit" class="btn btn-primary" value="Submit" />  
                                </p>
                            </form>

                            <?php
                                $miles = $_POST['mile']; //This is line 130

                                // How many km is one mile?
                                $onemile = 1.609344;

                                $totalkm = $miles * $onemile;

                                print "<p>$miles miles is $totalkm kilometer.</p>";


                            ?>

Thanks in advance

[Psycho]

First a tip: Create your logic (i.e. PHP ) at the top of the script and create variables for the output. Then put the presentation (i.e. HTML) at the bottom of the script using just echo's for the applicable output content.

 

For your issue, do a check to see if the value was submitted before trying to access the POST variable.

<?php
 
$output = '';
$miles = '';
if(isset($_POST['mile']))
{
    // How many km is one mile?
    $onemile = 1.609344;
 
    $miles = floatval($_POST['mile']);
    $totalkm = $miles * $onemile;
     $output = "<p>$miles miles is $totalkm kilometers.</p>";
}
 
?>
 
<h3 class="section-heading">Convert Miles to Kilometer II.</h3>
<hr class="primary">
<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>" style="margin-top: 20px;">
    <p>Add Miles:
        <input type="text" class="form-control" placeholder="miles" name="mile" size="2" value="<?php echo $miles; ?>" />  
    </p>
    <p><button type="submit" class="btn btn-primary">Submit</button></p>
</form>
 
<?php echo $output; ?>
 

Edited September 27, 2016 by Psycho

[dtommy79]

Thanks