tablesorter parser img tag not working
I have a column that either has a checkmark image tag <img src=...> or nothing and want to sort on it, so I setup a parser but it is not working, any idea what I am doing wrong?
$.tablesorter.addParser({
id: 'checkmark',
is: function(s) {
return false;
},
format: function(s) {
if (s.substring(1,5)=="<img") //also tried (s!="")
return 1;
else
return 0;
},
type: 'numeric'
});