Is there a way to use autocomplete without JQuery UI cause JQuery UI\'s footprint is too large (including its CSS) ?
or is there any alternative plugin or something
You can build your own that does not depend on JQuery UI, its a very simple idea of trigger field onchange(), issue an AJAX call to get result that matches what you typed so far, and populate some field with a div or drop down below or near it. And on select of the div or drop down, you populate your trigger field with selected value.
I know that Jquery Autosuggest does not use JQuery UI but does require JQuery.