This form creates unique passwords for websites that require a secure password, such as any site wanting personal information or a credit card number.

This form combine a single master password with a key unique to each website. Have one good master password that you can remember and use only for this purpose. For the site key, I recommend some version of the website name, following a rule that you can easily remember.

Save this form on a webpage that you can always reach. The javascript performs all calculations in your browser.

If someone learns your password for one site, they cannot easily derive the password for other sites. They would need to perform a dictionary attack against both the master password and site key, then guess the key for other sites.

Some people invent passwords for each site and save them in an encrypted file. That encrypted file then requires extraordinary security, unlike this javascript page.

I recommend you email the html for this page as an attachment to a webmail account that you can access anywhere.

I also recommend keeping a private list of those sites for which you use this system.