Stop browser from filling textboxes with details

I’ve run into a really annoying problem, and I’m hoping it’s just a setting I’ve missed. I’ve got an ASP.NET application which allows users to enter their username/password in various places (e.g. login, change password, change username etc..). When I logged in, the browser asked if I would like to store the user details. Usually, I click ‘no’, but this time I decided to click ‘yes’. Now, certain textboxes in my form are prefilled with the username or password. Is it possible to remove these, as they sometimes appear in textboxes which shouldn’t be prefilled. I tried setting AutoCompleteType=none and Text='' but it still gets prefilled. The textboxes don’t have much in common, except the same CssClass and, for password boxes, TextMode=password. The names are different, although sometimes they include the word name (e.g. fullName, userName). Is there a way to stop the browser from filling certain textboxes?

How to set autocomplete=off globally for ASP.NET application?

We have a mature application which handles sensitive data and has grown to several hundred pages and controls. It is now a requirement to set autocomplete=off for all the forms and textboxes in the entire application. I don’t believe there is a global web.config setting that would do this, so what would be the best way? My initial thought was to use a PageBase class (which all pages inherit from) to dynamically find all Form and TextBox controls and dynamically add the attribute autocomplete=”off”. Does this seem reasonable or is there a better way? Thanks for any recommendations.