Hi Pam,
You'll need to get your browser to store your username and password, along with the URL pointing to the site that's prompting for login information. In the Firefox browser on Linux, for example, under Edit->Preferences->Security there is a checkbox labeled "Remember passwords for sites" that must be checked. When you fill in the username and password for the first time at a site, you are prompted by Firefox saying "Do you want to remember the login information for this site?".
Answering "Yes" causes Firefox to store the site URL (
http://forum.loinc.org) along with the username and password just entered.
The actual location of this setting will vary with the particular browser and operating system. What are you using?
Hope this helps,
Ron