Integrating with the Windows 8 environment - Build Windows 8 Apps with HTML5 and JavaScript - page 213

FIGURE 9-6 Getting the name of the selected file.
You don't need to take any special care to get the name of a file or its file type. Three properties
are available: name, displayName, and fileType. . If you need to read some additional file properties
(such as, size or date), then you need a call to getBasicPropertiesAsync , as shown below:
savePicker.pickSaveFileAsync().then(function (file) {
if (file) {
file.getBasicPropertiesAsync().then(function (basicProperties) {
TodoList.alert(file.name + "(" + basicProperties.size + " bytes)");
});
}
});
File properties are split in three groups: built-in, basic, and extended. Built-in properties are name
and file type, and they are retrieved along with the file content. Basic properties include size and
dateModified; ; basic properties must be retrieved via a call to getBasicPropertiesAsync . Extra properties
must be accessed via a preliminary call to retrievePropertiesAsync . Here's an example:
file
.properties
.retrievePropertiesAsync([fileOwnerProperty, dateAccessedProperty])
.done(function (extraProperties) {
TodoList.alert(extraProperties[dateAccessedProperty]);
}
Typical properties you retrieve in this way are fileOwner and dateAccessed.