Pretend that all browser windows are active by spoofing the visibility state event
By installing this extension a small script is injected into every webpage which overwrites the "document.visibilityState", "document.hidden" properties to pretend the tab is always in the active state (document.visibilityState = 'visible' and document.hidden = false). This is useful for the webpages that check your visibility state before loading resources like many music webpages. By installing this extension even if the page is opened in the background page, the player will start immediately like the page is loaded on an active tab. Note that this extension also supports "document.mozHidden" on Firefox and "document.webkitHidden" on Chromium browsers. Also, it blocks the "visibilitychange", "webkitvisibilitychange", and "mozvisibilitychange" events that are emitted when the page visibility status changes.
Note that at the moment there is no exception list, so the extension injects the script on all HTTP and local HTML pages. You need to disable the extension from the options page if you need to bypass it.