var picker = new launchbox.DocumentPicker();

// Optionally, configure picker to pick documents only from device library ..
picker.source = "library";
// .. or try to capture new document using camera ..
picker.source = "capture"; 

​// Optionally, filter out document types which you are interested in ..
picker.type = ["image", "video"];
// .. or ..
picker.type = "audio";

// And optionally provide some parameters :
picker.imageParams = {saveToLibrary : true, quality : 60};
picker.videoParams ...

// And finally pick document ..
picker.pick()
     .then(function(fileEntry) {
         // If document is picked successfully here you obtain
         // instance of File API 'FileEntry' object.
         // You can open it using launchbox.DocumentViewer API or 
         // upload it to server using launchbox.FileTransfer API.
     })
     .catch(function(error)) {
         // Error handling.
     });