PHP如果使用if isset进行GET

Question

I am new to PHP and I would like to know the correct way to display error in index.php but only if there are errors otherwise it does nothing.

The page index.php send the form to login.php if there are errors it return the error to index.php like this:

index.php?error=1

Then in index I have the follow code but it feels like the page got slow

<?php
if ($_GET['error']==1){echo "We show error 1 ...";}
if ($_GET['error']==2){echo "We show error 2 ...";}
if ($_GET['error']==3){echo "We show error 3 ...";}

?>

How can I fix it the correct way? Some uses the if isset but I dont know how to use this funtion it give me errors

Answer 1

Any time you have repetition like you have presented in your example, try using a function or a storage array. Though your code probably isn't going much slower, try something like this:

<?php
// List of errors. If you do it this way, you can keep
// adding errors without adding if/else
$error[1]= "We show error 1 ...";
$error[2]= "We show error 2 ...";
$error[3]= "We show error 3 ...";

// Check if set
if(isset($_GET['error']) && isset($error[$_GET['error']]))
    echo $error[$_GET['error']];
?>