I personally use this:
<%= f.text_field :name, :autocomplete => "off" %><div class="auto_complete" id="customer_name_auto_complete"></div>
And add the auto-generated Javascript and CSS manually. Here's the Javascript:
new Ajax.Autocompleter('customer_name', 'customer_name_auto_complete', '/customers/auto_complete_for_customer_name', {
method:'get',
paramName:'customer[name]',
minChars: 3
});
and here's the CSS:
div.auto_complete {
width: 350px;
background: #fff;
}
div.auto_complete ul {
border:1px solid #888;
margin:0;
padding:0;
width:100%;
list-style-type:none;
}
div.auto_complete ul li {
margin:0;
padding:3px;
}
div.auto_complete ul li.selected {
background-color: #ffb;
}
div.auto_complete ul strong.highlight {
color: #800;
margin:0;
padding:0;
}