Password Regular Expression

^(?=.{6,10})(?=.*[a-z]{1,})(?=.*[0-9]{1,})(?=.*[A-Z]{1,}).*$

(?=.{6,10})

6 characters minimum.
10 characters maximum.

(?=.*[a-z]{1,})

Must contain at least one lower case letter.

(?=.*[0-9]{1,})

Must contain at least one number.

(?=.*[A-Z]{1,})

Must contain at least one upper case letter.