Join MDN and developers like you at Mozilla's View Source conference, 12-14 September in Berlin, Germany. Learn more at


Indicates whether or not Software Installation is enabled for this client machine.

Method of

InstallTrigger object


Boolean enabled (); 




True if Software Installation is enabled for this client machine; otherwise, false. The method reflects the value of the Software Installation preference in the user interface, and of the xpinstall.enabled preference in pref.js.


The following code uses the startSoftwareUpdate method to unconditionally trigger a download from http://royalairways/royalpkg.xpi as long as Software Installation is enabled on the browser:

if (InstallTrigger.enabled() ) {
    InstallTrigger.startSoftwareUpdate ("");

Document Tags and Contributors

 Contributors to this page: Sheppy, ethertank, trevorh, Fredchat, Callek, MozillAisawesome, Rod Whiteley
 Last updated by: Sheppy,