Observes this form and submits the form when any field changes.
Both the form and the field will be assigned a CSS class
while the autosubmitted form is loading.
The programmatic variant of this is the
This will submit the form when either query or checkbox was changed:
<form method="GET" action="/search" up-autosubmit> <input type="search" name="query"> <input type="checkbox" name="archive"> Include archive </form>
The number of miliseconds to wait after a change before the form is submitted.