method allKeys

This method returns an array that contains all of the keys within the dictionary.

var dictObj = shell.serviceManager.basics.dictionary;
dictObj.setValueForKey("John", "FirstName");
dictObj.setValueForKey("Doe", "LastName");
dictObj.setValueForKey("35", "Age");

//get all the key names into an array object.  See array class for more information
var allKeys = dictObj.allKeys();
for (var x = 0; x < allKeys.count; x++)
{
//dictObj.valueForKey(allKeys.getValue(x))
//can be used to get the value for the particular key
}