The main thing regarding the function named mysql_connect is totally deprecated from PHP v5.5.0 and not supported.
You can check with the official documentation for PHP mysql_connect().
Instead of this, you can use the PDO function
Best [Solution] How to enable mysql_connect in PHP 5.6 and 5.5
For Suppressing the message due to depreciation and to [be aware of other depreciation in other different codes] you can use the prefix the connect with “@”.
<?php
$connect = @mysql_connect('localhost','root','');
mysql_select_db('dbname');
?>
There are also many users who get the error: “Undefined function mysql_connect()”.
For this, you have to check first PHP MySQL extension module is being loaded.
Check first PHP info.
<?php
phpinfo();
?>
If it’s not there then you can check the php.ini file.
;extension=php_mysql.dll
please remove “;” before
extension=php_mysql.dll
Conclusion
Hope this article helps you in fixing How to enable mysql_connect in PHP 5.6 and 5.5.