Hi, I am writing some web app, from web app I want to know if skype is installed or not on a machine from which web page is called. Is this possible? if yes how?
It should work at least on Firefox, IE and chrome on windows. If it works on Linux and Mac then it will be great.
Thanks in advance.
No, I don't believe you can detect this. JavaScript does not have access to machine configuration like this. User agent strings are the most common way for JavaScript to learn about the underlying machine, and Skype doesn't appear to publish any data there.
You can use a Java or ActiveX agent, or a plain executable, to report that data back to you (the user would have to allow that, of course), or just ask the user.
Well, you can try the old trick with changed style of visited links. So if a potential user has visited http:\skype.com, chances are she's got Skype installed.
Related read: http://hacks.mozilla.org/2010/03/privacy-related-changes-coming-to-css-vistited/
I believe a Java (not javascript) applet on a webpage is able to which programs are installed on the computer of someone who visits your site, although they might have to give the applet permission to run first.