It is possible, when you spy something you can use a read stage to record a value, naming akin to what you see in the Application Modeller.
Example, if you wanted to find the X, Y value of something in HTML you could use a read stage to read value from the element and in the input below type the name of the X field, then create another read for the Y stage also.
EDIT: wrote navigate stage, meant read stage. and the method you're looking for is Get Window Attribute. There are a few others methods there to use that could be useful to you also
