9. A method for opening a document from a user's computing device, the document corresponding to a document URL, the method comprising: registering a capability of a first application installed on the user's computing device to process document URLs of a specific type, the first application configured for native operation outside of a web browser on the user's computing device, wherein the web browser on a user's computing device tracks a declaration of a document URL type in a manifest of the first application of the capability of the first application to open a document corresponding to a document URL which conforms to the declared document URL type, and wherein the web browser maintains a registry of document URL types associated with applications including the first application installed on the user's computing device, the document URL types representing types of document URLs that the applications are coded to open or process, the registry of document URLs types being maintained as a table of the declared document URL types registered by the applications; when a navigation event on the user's computing device leads to a navigated-to-document URL that is of the specific type of document URLs registered to the first application on the user's computing device, presenting a selection dialog permitting the user to select whether the first application should be launched outside the web browser to process the navigated-to-document URL to open the document; and based on a user selection in the selection dialog, redirecting the navigated-to-document URL to the first application and launching the first application on the user's computing device to open the document corresponding to the navigated-to-document URL by one of using the navigated-to-document URL redirected to the packaged first application to extract the document from the navigated-to-document URL and using the redirected URL as a unique ID to extract the document from a local cache.
9. A method for opening a document from a user's computing device, the document corresponding to a document URL, the method comprising: registering a capability of a first application installed on the user's computing device to process document URLs of a specific type, the first application configured for native operation outside of a web browser on the user's computing device, wherein the web browser on a user's computing device tracks a declaration of a document URL type in a manifest of the first application of the capability of the first application to open a document corresponding to a document URL which conforms to the declared document URL type, and wherein the web browser maintains a registry of document URL types associated with applications including the first application installed on the user's computing device, the document URL types representing types of document URLs that the applications are coded to open or process, the registry of document URLs types being maintained as a table of the declared document URL types registered by the applications; when a navigation event on the user's computing device leads to a navigated-to-document URL that is of the specific type of document URLs registered to the first application on the user's computing device, presenting a selection dialog permitting the user to select whether the first application should be launched outside the web browser to process the navigated-to-document URL to open the document; and based on a user selection in the selection dialog, redirecting the navigated-to-document URL to the first application and launching the first application on the user's computing device to open the document corresponding to the navigated-to-document URL by one of using the navigated-to-document URL redirected to the packaged first application to extract the document from the navigated-to-document URL and using the redirected URL as a unique ID to extract the document from a local cache. 17. The method of claim 9 , wherein launching the application on the user's computing device to open the document corresponding to the navigated-to-document URL includes opening a byte-stream from the application to the document.