Supposedly, an unlimited number. In reality, too many might make your browser crash. Try separating them out into different windows to make this less likely.
maximum tabs that can be opened are "420" try it
The firefox tabs are used to keep multiple websites running in a single window, cutting down on the necessary memory to run the websites.
You could get tabs if you are using I.E.7, Firefox, and any other browsers that supports tabs. You might be able to get tabs in add-ons.
The key command on the keyboard to switch between tabs in Mozilla Firefox 2 and above is 'Ctrl + Tab'.
Ctrl W
Upon starting it up, Firefox will reload all of the tabs that were open at the time that Firefox was last closed by using its built in Session Restore feature. To change the startup options in Firefox go to, Tools > Options > Main and choose from one of the three options provided in the Startup section. Show my windows and tabs from last time Show my home page Show a blank page
Go to tools -> options -> tabs -> Check the square that says "Always show the tab bar".
Right click any tab, and select "Reload all tabs."
on the drop menu, click file, new tab. if you have an older version of Firefox (Firefox 1.0), the program may not be able to open multiple tabs.
On Firefox, Ctrl + Shift + W closes all currently open tabs.
as many as you want and you have add ons for easier working and managing tabs.One of them is Tab Mix Plus you can install it from firefox add ons site
If this is about Firefox, then you simply open the Add-ons window via the Tools menu. At the top, there will be 4 tabs: Get Add-ons, Extensions, Themes, and Plug-ins. All the add-ons you have installed on Firefox will be categorized under the last three tabs, most likely Extensions.