Call ASP.NET PageMethod/WebMethod with jQuery – returns whole page

jQuery 1.3.2, ASP.NET 2.0. Making an AJAX call to a PageMethod (WebMethod) returns the full/whole page instead of just the response. A breakpoint on the page method shows it’s never getting hit. I have the [WebMethod] attribute on my method, and it is public static, returns string and accepts no params. I even tried adding [ScriptService] at the top of my class to see if it helped, but it did not.