Comparing Firefox and Opera(ZT)

In Firefox, when you have a lot of tabs open and switch from one tab to another, there's a significant delay. It seems like the tab switching function loop 1000 times too many before it actually switches to the tab. Opera doesn't have that problem.

With Firefox, starting up takes forever and navigating the UI menus and the whole interface in general, is not as responsive as it should be. Opera doesn't have those problems.

In Firefox, you can't really configure plugins much. In the 1.5 betas, you can do some configuration, but a lot of the settings don't have any effect. There's no option to turn of plugins. Opera doesn't have those problems.

In Firefox, there's no g keyword for the address bar to search google. You can add this with a bookmark and a keyword. Opera already has this set up without the need for a bookmark.

In Firefox, you can't add a separate go button for use with the google search box. Opera doesnt have that problem.

In Firefox, you can't minimize a tabbed page inside the main window. You therefore can't left-click on a tab to minimize it and have Firefox focus on the last unminimized tab. You can't cascade and tile pages. You can't have a minimize, maximize/restore, and close page for each tab. Opera doesn't have those problems.

In Firefox, left-clicking on a bookmark no longer opens the bookmark in a new tab and focuses it. Opera doesn't have this problem.

In Firefox, zooming only increases/decreases text. Opera increases/decreases everything.

In Firefox, the downoad manager doesn't open in a new tab. Opera doesn't have that problem.

In Firefox, there's no F12 quick preferences menu. This is not a problem in Opera.

In Firefox, there's no "continue from last time" option. Opera doesn't have that problem.

In Firefox, you can't specify how you want popups handled. In Opera, this is not a problem.

In Firefox, there's no right-click->open option so you can override link targets. This is not a problem in Opera.

In Firefox, F11 still shows tab bar. This is not a problem in Opera.

In Firefox, there's no Small Screen Rendering mode or fit-to-width mode. This is not a problem in Opera.

In Firefox, there are no mouse gestures. Opera doesn't have that problem.

In Firefox, you can't minimize to the tray. Opera doesn't have that problem.

In Firefox, you don't have very many buttons to customize the toolbar with. You can't easilly add new buttons and you can barely customize the toolbars. Opera doesn't have those problems.

In Firefox, you can't control where the progress bar is. This is not a problem in Opera.

In Firefox, you have a sidebar, but you can't add anything to it. You can't control its position either. Opera doesn't have those problems.

In Firefox, you don't have any session management. That's not a problem in Opera.

With Firefox, you can't have 2 firefox processes that use different profiles, running at the same time. Opera doesn't have that problem.

In Firefox, textareas don't force wrapping and if you have long text with no spaces, you'll get a horizontal scrollbar, no matter what. Opera doesn't have this problem.

In Firefox, the classid attribute for the object tag makes Firefox not use the data attribute, which can cause it to fail loading the plugin. Firefox only honors the codebase attribute for the classid attribute instead of both the classid and data attribute. Opera doesn't have those problems.

In Firefox, when loading the realplayer plugin, paramaters specified via param tags for the object tag have no effect. Opera doesn't have that problem.

In Firefox, when setting display:table on an element, it strips white-space before applying anonymous table elements, which causes missing white-space in the content. Opera doesn't have this problem.

In Firefox, document.createNodeIterator does not work; only createTreeWalker works. Opera doesn't have that problem.

In Firefox, javascript execution speed is slow. Opera doesn't have that problem.

In Firefox, when a java applet fails to initialize and you later close Firefox, the Firefox process often remains open and you have to kill it manually. Opera doesn't have that problem.

In Firefox, the framespacing attribute for the frameset tag doesn't work. You have to use the frameborder attribute, which is oddball. Opera doesn't have that problem.

In Firefox, there are no content preferences that allow you to toggle gif animation, sound, frames etc. Firefox does have a frame toggle in about:config. Opera doesn't have these problems.

In Firefox, there's no "close all" option for tabs. This is not a problem in Opera.

In Firefox, there's a buffer for commands. For example, if you have a lot of tabs open and middle-click faster than Firefox can close the tabs, the number of clicks builds up and Firefox ends up closing the next available tab till the buffer is empty. This is a problem because you end up closing more tabs than you want. This is not a problem in Opera.

In Firefox, if you ctrl+w to close a page and there's only one page, it closes Firefox completely. This is not a problem in Opera.

In Firefox, because the size of each tab is the size of the main window, javascript screws up the size of the main window. Opera doesn't have this problem.

notes: Those comments reflect Opera vs. Firefox, not Firefox + "3rd party extensions" and Opera + "3rd party plugins/programs".