Js-autosuggest is a project mainly written in JavaScript, it's free.
a lightweight jQuery plugin for autosuggest searching on goingslowly.com
$('#autosuggest').autosuggest(
{
data:{}, // JSON data to search
delaySearch:100, // delay from last typed letter before searching
delayClose:1500, // delay to close results after mouseout
minChars:3, // minimum number of characters required to start search
key:'name', // data object property name for field to search
val:'url', // data object property name for url of hit
prefix:'prefix', // data object property name for prefixed hits
// this should be placed at the end of the object
// so they display first
offsetTop:0, // offset placement of results from top
offsetLeft:0, // offset placement of results from left
highlight:true // true of matching portion of word should be highlighted
};
var blog_entries =
[
{
name:'My First Blog Entry',
url:'http://www.blog.com/blog-entry-one/'
},
{
name:'Blog Entry Number Two',
url:'http://www.blog.com/blog-entry-two/'
},
{
name:'Title of Third Blog',
url:'http://www.blog.com/blog-entry-three/'
},
{
name:'Blogs',
url:'http://www.blog.com/topic/blogs/',
prefix:'Topic:'
}
];