Javascrtip snippet for updating filters on a page. Hook up to onchange for a selector

function change_filter(input, accept_blank, query_string_var)
{
  var accept_blank = (accept_blank) ? accept_blank : false;
  if ((input && input.value) || (input && accept_blank))
  {
    filter_name = (query_string_var) ? query_string_var : "filter"; 
    url = add_or_update_query_param(filter_name, input.value)
    window.location.href = url
  }
}