can i use both mysqli for form input and mysql for showing data using old cs6?

Do not use Dw's server behaviours, unless you know how not to use the php connection scripts Dw creates.

The main reason the old mysql was dropped and no longer supported by both Dw and php itself, is because the password function used by the mysql extension was insecure, and php could not fix the problem without backwards compatibility problems.

The password function was used by every page that contained Dw server behaviours.

iamdpk  wrote hello guys , i m working on a project i m using mysqli in that, but have used only mysqli for form inputs like login or reg. now i m creating pages to show only data using recordset, so my question is " is it still secure? " .

I would not worry about security too much, but the question is why are you using mysqli for login and register pages and mysql for getting data on your other pages, doesnt seem like good forward planning to me.

Youve obviously had to write your own code solution for the login and registration pages using mysqli so why not do the same for the other pages, rather than use the outdated DW server behaviours.

Just be aware you can't mix and match mysqli and sqli on the same page but you should by now not be even considering  using mysql

There will be no change in security, keeping in mind that PHP<7/MySQL is less secure than PHP>5/MySQLi