changedFieldNames.js

// Make a call to GlideRecordUtil and get the entire current object.
var gru  = Packages.com.glide.script.GlideRecordUtil.get(current);

//Invoke the function called getChangedFieldNames();

var fieldsChangedList = gru.getChangedFieldNames();

// One important thing to note is that, the object thats here is a Java object, so we will now use j2js to convert it into a 
// Javascript Array.

// j2js is a Script Include, which recursively calls itself and converts a Java object into Javascript Object, in this case an array..

jsfieldsChangedList = j2js(jsfieldsChangedList);