Ajax callback function $ (this) has no effect on solution __ function

The following jquery code is expected to work.

$ (". Derek"). each (the function () {
		$ (this). Click (function () {
			var params = $ (this). Parent (). Serialize ();			
			var obj=$ (this). Parent (). Siblings ("Div#caskcontent");
			var form=$ (this). parent ();
			$.ajax ({
				URL: "editcaskcontent",
				type: "Post",
				Data:params,
				dataType: "JSON",
				success: Function (e) {
					obj.empty ();
					Obj.html ("<font color=\" #00AA00, "> Cross-examine:</font>");
					Obj.append (e.caskcontent);
					Form.toggle ();
					Alert ("modified successfully.") ");
				},
				error:function (e) {
					alert (e);
				}
			}
	);});

As you can see, before I made the AJAX request, I defined two variables, obj and form, to store two jquery objects, respectively. If you use the $ (this) in the Ajax callback function, the practice proves that you can't get any objects. Specific reasons, I hope the great God message advice.