# the old way, as I've seen a few times
# to get to our data we'd do a string sub to remove "thing_", leaving only the id we care about
# which works, but isn't very semantic, in my opinion
<div class="thing" id="thing_<%= thing.id %>"> stuff goes here! </div>

# here's the HTML5 way
<div class="thing" data-thing_id="<%= thing.id %>"> stuff goes here! </div>

# now we can find that ID very easily in jQuery
# which would be really useful if we want to do an AJAX call using that particular id as a parameter.
var thingId = $(this).attr(data-thing_id);
# example ajax post with this variable:
$.post("things/example_action/" + thingId);

# and we can use the CSS selector to find that element easily as well (again with jQuery)
# this would be useful AFTER we make an AJAX call and want to update that particular element on the page.
# updating our one specific element is better than re-rendering an entire section
$(".thing[data-thing_id='<%= @thing.id %>']");