You can save our web editors to your computer so that they are available when you are not connected to the internet. We are continually improving the editors, so you should use the online versions whenever you have internet connectivity and if you need to access it offline, grab the latest version every few months.
To save an editor locally, access the web editor page using Google Chrome.
Select File --> Save Page As...
In the Save dialog, select a folder and set Format to Webpage, Complete.
Click Save.
To use the editor from your computer, open the HTML file (e.g., "Particle Editor.html") using Google Chrome. If Chrome is your default browser you can double click on the HTML file to open it. Otherwise, right click on the file and select Open With --> Google Chrome. You can avoid using the Open With menu by associating Google Chrome with the editor's HTML file (varies by operating system).
Remember to update your saved copy of the editor regularly, to make sure you are getting the latest updates and features.