It is not that straight forward to get the xml/json/html outpt for a google spreadsheet.
First thing we need to do is to publish the sheet under File -> publish to the web….
Here is what you may get
Now you have the html version.
After you get the shee-id, what you need to do is to find the grid id of the sheet use:
After open the above URL, we get a summary of the published sheet. Then we can find the grid id under the entry element:
Now using the combination of GRID-ID and YOUR-SHEET_ID, we should be able to get the xml/json output by:
XML —-> http://spreadsheets.google.com/feeds/list/YOUR-SHEET_ID/GRID-ID/public/values
JOSN —-> http://spreadsheets.google.com/feeds/list/YOUR-SHEET_ID/GRID-ID/public/values?alt=json-in-script