PHP Notice: Undefined Index

Okay, I keep getting this error when someone accesses the file.

Code:

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PHP Notice:  Undefined index:  Ex in C:\\Server\\172.16.1.35\\WhosOnline.php on line (2, 3, and 33)

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I noticed that in every line, there is something like this.

PHP Code:

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if ($_GET["Ex"] == "false") echo "</pre>"; 


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Now, sometimes, there will not be a ?Ex=false, so I made it to this.

PHP Code:

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if ($_GET["Ex"])
{
    if ($_GET["Ex"] == "false") echo "</pre>";
} 


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I still get the error that the index is undefined, and this snippet is not working how I thought it would, so how do I check if it is undefined, so it will stop giving me that error.

i think this is what you want:

Code:

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if (isset($_GET["Ex"]))
{
        if ($_GET["Ex"] == "false") echo "</pre>";
}


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PHP is a loosely typed language. That means that variable types automatically adapt. You shouldn't need quotes around the false for it to act as boolean.

PHP Code:

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if (isset($_GET["Ex"])) {
  if (!$_GET["Ex"]) {echo "</pre>";}
} 


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Okay, I knew it was something like isset().