EDIT: I\'ve gotten the \"famous question\" badge with this question, so I figured I\'d come back to it and stick what happened to me right at the very tippy
jQuery.parseJSON will convert the json string into json object so alert(obj) will show you [object Object] since it is an object.
jQuery.parseJSON
[object Object]
If you want to see what obj contains then use console.log(obj) and then check console log message.
obj
console.log(obj)