php error in getting form value

PHP error in getting form value

Error example:

<?php
$index = 1;
$filename = $_POST[&#39;filename&#39;];
echo $filename;
?>

$ _POST ['filename '] From another page:

<?php
$db = substr($string[0],14) . "_" . substr($string[1],14) . "_db.txt";
?>
<input type="hidden" name="filename" value="<?php echo $db; ?>">

Solution:

First method: isset judgment

if(isset($_POST['filename'])){
    $filename = $_POST['filename'];
}if(isset($filename)){ 
    echo $filename;
}

Second method: Shield warning

Modify the error display mode under the error configuration in php.ini: Modify error_reporting = E_ALL to

error_reporting = E_ALL & ~E_NOTICE

Restart after modification Download the APCHE server to take effect.

Third method: Custom function

function _get($str){ 
$val = isset($_GET[$str]) ? $_GET[$str] : null; 
return $val; 
}

Pass the value through this function.

The fourth method: @

Add @ before the notice code. @ indicates that there is an error in this line or a warning not to output, @username=_post[ 'username'];

Recommended tutorial: PHP video tutorial

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