Incident. Locally, this code worked. Uploaded to hosting error indicates line 4.
mysql_connect ("localhost", "root", "2") or die (mysql_error ());
Writes
Fatal error: Uncaught Error: Call to undefined function mysql_connect ()
Answer 1, authority 100%
This extension has been deprecated since PHP 5.5.0 and removed in PHP 7.0.0 . Use MySQLi or PDO_MySQL instead. Maybe the hosting has version 7 PHP .
Use mysqli_connect () :
$ link = mysqli_connect ("127.0.0.1", "my_user", "my_password", "my_db");
if (! $ link) {
echo "Error: Unable to connect to MySQL." ... PHP_EOL;
echo "Error code errno:". mysqli_connect_errno (). PHP_EOL;
echo "Error text:". mysqli_connect_error (). PHP_EOL;
exit;
}