Попробуйте следующее:
function split( val ) {
return val.split( /,\s*/ );
}
function extractLast( term ) {
return split( term ).pop();
}
$( "#search" )
.autocomplete({
minLength: 0,
source: function( request, response ) {
response( $.ui.autocomplete.filter(
items, extractLast( request.term ) ) );
},
focus: function() {
return false;
},
select: function( event, ui ) {
var terms = split( this.value );
terms.pop();
terms.push( ui.item.value );
terms.push( "" );
this.value = terms.join( ", " );
return false;
}
});
СМОТРИТЕ DEMO