Here is a not-too-ugly minimal example of JQueryUI Autocomplete w/o needing to bring in all of the CSS from Jquery
No-Library (pure JS), HTML, CSS, JavaScript
jQuery 1.11.0, HTML, CSS, JavaScript
Ex. 4.2
jQuery 1.7.2, HTML, CSS, JavaScript
jQuery 1.9.1, HTML, CSS, JavaScript
jQuery 1.8.3, HTML, CSS, JavaScript