I have a filter which requires an id-parameter (GET). This works fine when I add the parameter in the navigation links. But when I stay at the same site (e.g. ajax calls), the filter shouts and screams, because the id-parameter is lost.

Is there a chance to ignore the filter if the request come from ajax? 
something like

```
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    if (FacesContext.getCurrentInstance().isPostback()) {...}
    ...
}

```

?