The ejSlider-Control hides the input-field and only displays the current value when the thumb is moved. I did not find a setting to always display the value.
Playing around in the browser's console, I found that I can make the input visible using
$("input[name='foo']").attr("type","number");
But it then overlaps the scale. I guess it could fiddle more to separate the fields, make the input readonly etc. - but maybe there are hurdles I didn't think of, or maybe someone has already found a way to do that - or maybe I am missing a switch somewhere. So I thought I'll better ask here before starting out... ;-)