SecurityXploded is an Infosec Research Organization offering 200 FREE SecurityPassword Recovery Tools, latest Research Articles and FREE Training on Reversing. Browser Plugins vs Extensions the difference. Overloaded terms. One of the least understood concepts in the Browser Plugin world is browser plugins. What they are, and even more what they are not. Probably at least once a week I answer a question somewhere on a forum or on the comments on this blog and say You cant do that with a plugin you need an extension. Many people confuse plugins and extensions in the browser world. They sound like they should be the same thing, but in fact they are very different. What you can do with a plugin. A plugin is, quite simply, a third party library that plugs in to the browser that can be embedded inside a web page using an lt embed tag or a lt object tag. Many of them then draw pretty pictures or animations, though thats not required. Many allow you to talk to them through javascript, though thats not required. In short, a plugin affects only a specific page in which it is placed. Examples of common plugins include Macromedia Flash. Microsoft Silverlight. Apple Quicktime. Adobe Reader at least this includes a plugin in addition to the rest of the applicationSome plugins respond to a mime type and can run in place of the page, such as Adobe Reader, which allows you to view PDF files in your web browser. Again, however, it affects only that page, and no others. In Firefox, Chrome, Opera, and Safari, these plugins are usually called NPAPI plugins, since they are written using the NPAPI. In Safari, you could also use a Webkit Plugin. In Internet Explorer you would do this with an Active. X Control. What a plugin cannot do. Plugins have to either handle a mime type or be embedded into a web page. They dont get put there automatically. They dont create toolbars. They dont affect browser menus. They dont know about tabs, or even about other pages in the same browser process. They dont make coffee, tea, or hot chocolate, though they could be written to control an external appliance to do so if you really wanted. They dont automatically process the content of every web page loaded. But wait I hear you all cry. We have seen these magical things doneYes, I reply. Those are extensions. Extensions. Extensions, or add ons, can often do these magical things. They can add onto the browser UI, process pages that the browser loads. They do all sorts of things. However, they are not the same thing as plugins they affect the web browser itself, not really the page. They may affect a page as well, of course. In fact, you can even put a plugin inside an extension, at least in Firefox. However, if you write an extension for Firefox, youll probably have to write it again for Chrome, Safari, and IE one for each. Perhaps there is a framework out there for writing portable extensions, though. Its not really my area of expertise, so I dont know. Examples of extensions add ons And many, many, many more. Extensions can be written in different languages depending on the browser. In Firefox you can write them in C or javascript, and on Internet Explorer you write them as special Active. X controls called Browser Helper Objects, or BHOs. An extension could contain a plugin, but a plugin cant contain an extension. One very common way to install a plugin in Firefox is to use a. This is an extension. It may have a NPAPI plugin inside of it, but it is still an extension. It will not work on other web browsers, even though your NPAPI plugin may work perfectly fine on Chrome and Safari if installed in another way. Conversely, a plugin by nature does not include an extension. Fire. Breath. Nearly a year ago now I began a project called Fire. Breath, which is a cross platform browser plugin architecture. Fire. Breath is, frankly, awesome. You can literally get a plugin up and going in under 1. That means you can spend your time doing other more important things, like actually developing your functionality, rather than spending all your time figuring out how to deal with the plugin APIs. That said, Fire. Breath is a cross platform browser PLUGIN framework. It does not create extensions. It will never be able to create extensions. If you need an extension, you need something else. When not to use a plugin. ConvertHelper_4.png' alt='Firefox Helper Serial' title='Firefox Helper Serial' />Finally, and this is a topic that people seem to think is a little strange coming from me, there are many cases when it is not a good idea to use a browser plugin. In fact, a good rule of thumb is that if you can do what you need to do without one, dont use one. Why There are no really good ways to install browser plugins that will work 1. Firefox Helper Serial' title='Firefox Helper Serial' />Detect movement, then scare the heck out of an intruder with a high pitched alarm sounds and flashing lights. Does that sound funSerial key for DownloadHelper Firefox 4. We have the largest serial numbers data base. Once in a while, I see IP helperaddress command for broadcast applications such as DHCP clientBOOTP, NetBIOS and so on. As you know IP helperaddress is required. Video DownloadHelper is the most complete tool to extract videos and image files from Web sites and save them to your hard drive. Just surf the Web as you. XPI install only works on one profile in firefox. CAB install only works in Internet Explorer and is sometimes a little unreliable. Click. Once works only in Windows and only if. Net is installed. Java installers only work reliably and consistently on Mac OSMSI or EXE installers while being the best method IMHO require a little more work on the part of the user, and the average user is less savvy than you are, shall we say. Plugins have to take into account a large range of hardware types. If you use graphics libraries such as Open. Microsoft Point Generator Works 100% Percent. GL or Direct. X keep in mind that every graphics card works a little differently with these technologies. You will run into weird cases where your plugin doesnt work on someones computer. If your luck is like mine, that computer will belong to an executive at a fortune 5. Plugins dont work until they have been installed. This is a major limiting factor to uptake of your site. Many users dont want to install yet another plugin on their machine, and many get lost in the incredibly complicated task of downloading and running the installer. Moving on. If all of those things havent convinced you that what you want isnt actually a browser plugin great  Thats why Im still posting about this stuff. Despite all the reasons not to use a plugin, there are also a lot of cases where its a good idea.