InstallTrigger.startSoftwareUpdate

This is a very simple example of the InstallTrigger object's principal method, startSoftwareUpdate, which takes a string representing the path to the XPI and installs that XPI on the local machine.

 function triggerURL(url)
{
   InstallTrigger.startSoftwareUpdtate(url);
}
 // get the url to the .xpi from either a form 
// or text field entry. Then do:
 ... onclick="triggerURL(this.form.url.value);