未定义的索引/变量[重复]

"Notice: Undefined index: size in C:\Nginx\html\default.php on line 3"

I'm getting this error whenever I try opening my new game website. Does someone here have any ideas on how to fix this?

<?php
$size = $_GET["size"];

/** Default dimensions **/
$width = "960";
$height = "550";

/** Show **/
switch($size) {
    default:
        break;
    case 'large':
        $width = "1185";
        $height = "679";
        break;
    case 'huge':
        $width = "1792";
        $height = "1027";
        break;
    case 'tiny':
        $width = "706";
        $height = "405";
        break;
}
?>

</div>

Yes, you don't have size set in your request; thus, the index 'size' in variable $_GET is not set (i.e. undefined). If you request like so default.php?size=large it should be gone (if you don't do anything to unset it elsewhere).

Additionally you really should check whether it's set or not with somehting like:

$size = isset($_GET["size"]) ? $_GET["size"] : 'normal';

which will check if size=something is in your query and if it's not will default to 'normal'.