You can open facebook without a password or login to facebook without the use of your password. If you want to have access to your account but you have forgotten your password, then you can use the account recovery process to achieve that by clicking on forget password option. Logging into your Facebook account is now very easy, if you are using their application or a browser to access your account then you can save your password during the process of logging in.
They added this feature to make it easier for people to access their account, once the pop up appears asking you to save your password you can hit the save option. Then next time, if you want to log in it, will be just a click away without inputting your password. With the following explanations made above, you will be able to open facebook without password.