Cannot set property '_renderItem' of undefined jQuery UI autocomplete with HTML

I ran into the same problem...seems in later versions, it has to be .data("ui-autocomplete") instead of .data("autocomplete")

Since I just joined and can't comment on drcforbin's post above, I guess I have to add my own answer.

drcforbin is correct, although it is really a different problem than the one that the OP had. Anyone coming to this thread now is probably facing this issue due to the new version of jQuery UI just released. Certain naming conventions relating to autocomplete were deprecated in jQuery UI in v1.9 and have been completely removed in v1.10 (see http://jqueryui.com/upgrade-guide/1.10/#autocomplete).

What is confusing, however, is that they only mention the transition from the item.autocomplete data tag to ui-autocomplete-item, but the autocomplete data tag has also been renamed to ui-autocomplete. And it's even more confusing because the demos are still using the old syntax (and thus are broken).

The following is what needs to change in the _renderItem function for jQuery UI 1.10.0 in the Custom Data demo here: http://jqueryui.com/autocomplete/#custom-data

Original code:

.data( "autocomplete" )._renderItem = function( ul, item ) {
  return $( "<li>" )
    .data( "item.autocomplete", item )
    .append( "<a>" + item.label + "<br>" + item.desc + "</a>" )
    .appendTo( ul );
};

Fixed code:

.data( "ui-autocomplete" )._renderItem = function( ul, item ) {
  return $( "<li>" )
    .data( "ui-autocomplete-item", item )
    .append( "<a>" + item.label + "<br>" + item.desc + "</a>" )
    .appendTo( ul );
};

Note the changes for both autocomplete and item.autocomplete. I've verified that this works in my own projects.