1. A computer-implemented method for submitting and checking a password without additional user input, the method comprising: presenting a password entry form to a user, the password entry form having a text field for entering a password; wherein the password entry form is configured to accept passwords of variable length; detecting text input from the user; in response to detecting the text input from the user, displaying text characters in the text field; in response to the user entering text characters in the text field, submitting the contents of the text field for password verification; wherein the step of submitting the contents of the text field for password verification occurs without additional user input besides the user entering text characters in the text field; wherein the step of submitting the contents of the text field for password verification is performed repeatedly in response to the user changing the contents of the text field and is performed at least once before the user has completed entry of the password in the text field; at a first time, determining that a password submitted for verification is not a correct password of the user by retrieving a stored salt, adding the stored salt to the password submitted for verification or a function computed on the password submitted for verification and computing a hash of the result, comparing the resulting hash with a hash stored associated with an account of the user in a database, and determining that the hashes do not match; in response to determining that a password submitted for verification is not a correct password of the user, denying access to a protected computer resource; at a second time, determining that a password submitted for verification is a correct password of the user by retrieving the stored salt, adding the stored salt to the password submitted for verification or a function computed on the password submitted for verification and computing a hash of the result, comparing the resulting hash with the hash stored associated with the account of the user in the database, and determining that the hashes match; and logging in the user to provide access to the protected computer resource, and notifying the user that he or she is logged in; wherein the steps of detecting text input from the user and, in response to detecting the text input from the user, displaying text characters in the text field, are capable of occurring in parallel with the step of determining that a password submitted for verification is a correct password of the user.
7. The method of claim 1 , further comprising: in response to the user deleting text characters in the text field, submitting the contents of the text field for password verification, wherein the submission of the contents of the text field for password verification occurs without additional user input besides the user deleting text characters in the text field.