Users to enter URL

[cataiin]

I have this code:

<?php
$url = "http://www.example.com/";
$page = fopen($url, 'r');
$content = "";
while( !feof( $page ) ) {
$buffer = trim( fgets( $page, 4096 ) );
$content .= $buffer;
}


$start = "<text1>";
$end = "<\/text2>";


preg_match( "/$start(.*)$end/s", $content, $match);
$mytext = $match[1];
echo "$mytext";
?>

Now, I need a way for users to enter $url. I've tried with $_GET and to get current url (something like index.php?url=$url) but unsuccessful.