AIR can run a subset of JavaScript, with no ability to dynamically execute code when running in the application sandbox. According to Adobe, this restriction is designed to prevent malicious remote content from attacking a user's system. Because of this restriction, JavaScript frameworks that make use of dynamic JavaScript functions like eval() were not initially compatible with AIR. However, several frameworks including Dojo Toolkit, jQuery, and ExtJS were updated to run in AIR's application sandbox. Some frameworks like MooTools were already compatible.