Download and run the Companion.JS installer.
In order to work, Companion.JS needs a Microsoft Script Debugger Engine.
If you have one of the following software installed, you will already have this component installed :
If you don't one of those components installed, you can install the free Microsoft Script Debugger. It is free but cannot be redistributed, that's why it is not included in Companion.JS installer.
You'll need to tell Internet Explorer to enable the javascript debugger :
In Tools > Internet Options, select the Advanced tab and make sure to un-tick both check boxes:
You are set! You can check Companion.JS at work by visiting this dummy page.
If you want to make sure that CJS is properly installed go to Tools > Toolbars > Explorer Bar, Companion.JS should be there (and can be called from there as a matter of fact).
If Companion.JS is not working, you can check its status by going tothe About Box. Then you can copy/paste the information text and ask forsome help on the forum.
If the Companion.JS BHO is not registered (check this forum thread for more info), you can use this registry file to manually create the registry keys for the BHO.
Don't forget to change the file path to the CompanionJS.dll in this file : The current value is C:\\Archivos de programa\\Core Services\\Companion.JS\\CompanionJS.dll