Q:

How to clear the username and password in login form when they are wrong

I have a question 
When an user type a wrong username and/or password and joomla display a message about this error and I would like to clean both fields, how can I do that ?
thank you for you help

A:

Go to your Joomla root folder, from there:

go to: /templates/[your template]/html/mod_login
Backup default.php: cp default.php default.php.org
Edit default.php: vi default.php
And here's the tricky part, the thing you have to changes is different for each template, for example, in atomic template you should look for the line:

So the id of this field in this case is: "modlgn_username". Now you can use jQuery / Javascript and "clean" the value.

