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window.navigator.mozIsLocallyAvailable Redirect 1

« DOM Reference


Allows code to determine whether or not a given resource is available.


window.navigator.mozIsLocallyAvailable(uri, ifOffline);
  • uri the URI of the resource whose availability is to be checked, as a string.
  • ifOffline allows you to specify whether or not the offline resources cache should be checked; specify true to consider the offline resources cache.


var available = navigator.mozIsLocallyAvailable("my-image-file.png", true);
if (available) {
  /* the offline resource is present */
} else {
  alert("Certain needed resources are not available until you connect to the network.");


Note: Security exceptions can occur if the requested URI is not from the same origin.


None; however there is information available: Marking Resources for Offline Use


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Last updated by: Sheppy,