I want to run a local exe in my firefox extension javascript file, but ActiveXObject(\"WScript.Shell\") is work fine in IE,not in FF,how to run a local exe in js in firefox.
Since you've explicitly asked for an .exe then you can use nsILocalFile.launch()
:
https://developer.mozilla.org/en/Code_snippets/Running_applications
var file = Components.classes["@mozilla.org/file/local;1"]
.createInstance(Components.interfaces.nsILocalFile);
file.initWithPath("c:\\myapp.exe");
file.launch();
If you wanted to make it cross-platform you should look into nsIProcess