Have you considered using a button that would toggle the checkbox and capture the User and Timestamp with the same click?
This is the basic formula that I use for that. You'll probably want to tweak it so that the user lands back on the checklist instead of the record, but this is the gist:
var number box = IF([checkbox],0,1)
var text chk = "&_FID_68=" & $box;
var text usr = "&_FID_65=" & URLEncode(User());
var text time = "&_FID_65=now";
var text name = IF($box,"De-select Option","Select Option");
var text tk = "token";
var text URL = URLRoot() & "db/" & Dbid() & "?a=API_EditRecord&apptoken=" & $tk & "&rid=" & [Record ID#] &
$chk &
$time &
$usr &
"&rdr=" ;
var text Land = URLRoot() & "db/" & Dbid() & "?a=dr&rid=" & [Record ID#];
"<a class='Vibrant Success' & href='" &
$url &
URLEncode($land)
& "'>" & $name & "</a>"
------------------------------
Blake Harrison
bharrison@datablender.io
DataBlender - Quickbase Solution Provider
Atlanta GA
404.800.1702 /
http://datablender.io/------------------------------