Should I trim spaces in a password field

Question

Just wondering.

We usually trim a user name in various forms in our ASP.Net application, whats the best practices for password fields.

i.e. should we remove

Answer 1

You can use this to alert user that password include spaces or something like that.

if (/^\s|\s$/.test(password)) {
    //alert('Hey Watchout');
}

Triming password is not a good practice.

Hope this helps.

Answer 2

If you use the same trimming method when inputting in the db as you use when you select to test the password, the user's password will still work just fine.

There is of course a slight reduction of quality for that (very rare) user who choose to use white space in the beginning or end of her password.

Spaces inside passwords should never be a problem, tho.

In summary: I have not come across any good reason not to do a simple trim() for any input from web forms and the alike, passwords or not. The benefits, however, far outweighs the slight cost mentioned above.