get the value of a text variable

//  In my active Indesign document, there is a Text variable named myRevisionNR, type: modified text, which can be: "00", or "01" or "02", etc.

//  How can I display the "value" of my tex variable myRevisionNR?

//

//  Create text variable

var myDocVariables = app.activeDocument.textVariables;

var myDocVariablesNames = myDocVariables.everyItem(0).name;

//  The following sentence only displays: "myRevisionNR". But I want to see: "01", or "02"

alert(myDocVariablesNames[0])

//  Who can help me?