<?php if(isset($_GET['name'])): ?>

        Your name is <?php echo $_GET["name"]; ?>

<?php endif; ?>

<?php if(isset($_GET['name'])): ?>

        Your name is <?php echo $_GET["name"]; ?>

<?php endif; ?>

<?php if(isset($_GET['fname']) && isset($_GET['age'])): ?> //isset is important

        <br/>

        Your name is <?php echo $_GET["fname"]; ?>

        <br/>

        Your age is <?php echo $_GET["age"]; ?>

<?php endif; ?>

set_error_handler(function($errno, $error){

    if (!str_starts_with($error, 'Undefined array key')){

        return false;  //default error handler.

    }else{

        trigger_error($error, E_USER_NOTICE);

        return true;

    }

}, E_WARNING);

​

then 

ini_set ("error_reporting",  E_ALL & ~E_NOTICE & ~E_USER_NOTICE)

<?php if(isset($_GET['name'])): ?>

        Your name is <?php echo $_GET["name"]; ?>

<?php endif; ?>

<?php if(isset($_GET['name'])): ?>

        Your name is <?php echo $_GET["name"]; ?>

<?php endif; ?>

<?php if(isset($_GET['name'])): ?>

        Your name is <?php echo $_GET["name"]; ?>

<?php endif; ?>

<?php if(isset($_GET['name'])): ?>

        Your name is <?php echo $_GET["name"]; ?>

<?php endif; ?>

<?php

$array = array(

    'fruit1' => 'apple',

    'fruit2' => 'orange',

    'fruit3' => 'grape',

    'fruit4' => 'apple',

    'fruit5' => 'apple');

​

// this cycle echoes all associative array

// key where value equals "apple"

while ($fruit_name = current($array)) {

    if ($fruit_name == 'apple') {

        echo key($array).'<br />';

    }

    next($array);

}

?>