As we all aware, each browser (Mozilla, Safari, Google Chrome, Opera Mini and etc.) can open only one account of gmail at once. Let say you have 2 account of gmail and you want to open them at the same time using the browser Mozilla Firefox, here's how you do it:
1. First, login to your google mail account.
2. Then, at the right-above corner of the page, click on the account and choose Account Settings.
3. Then, at the Personal Settings column, look for the 'Multiple sign-in' and click on the 'Edit' link.
Click on the "Edit" link |