Debugging

Hi,
What is the best way for me to see the JSON data that is loaded by data tables (to debug server side code)?
Is there a function which I can use to output the data to the dom?
If I go straight to the server side URL, I don't see any data, but only a JSON string like:

{"id":-1,"error":"","fieldErrors":[],"data":[],"aaData":[{"DT_RowId":"row_0","LName":"English"},{"DT_RowId":"row_1","LName":"Dutch"}]}

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Moreover, in the above example I assume that DT_RowId is used internally by DT. I don't see any of my primary key names here.