Includes:

<link type="text/css" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.12/themes/smoothness/jquery-ui.css" rel="stylesheet" />
<script  type="text/javascript"src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.0/jquery.min.js"></script>
<script  type="text/javascript"src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.12/jquery-ui.min.js"></script>


Styling: 

<style>
	.ui-autocomplete {
		max-height: 100px;
		overflow-y: auto;
		/* prevent horizontal scrollbar */
		overflow-x: hidden;
    }
    /* IE 6 doesn't support max-height
    * we use height instead, but this forces the menu to always be this tall
    */
    * html .ui-autocomplete {
    height: 100px;
    }
</style>


script:

<script type="text/javascript">

$(function () {
    $(document).ready(function () {
        $("#tbSearchID").autocomplete({
            minLength: 2,
            delay: 300,
            source: function (request, response) {
                $.ajax({
                    url: "../WebServiceProxy.asmx/ValidateStringAjax",
                    data: "{ 'prefixText': '" + request.term.replace("'", "\\'") + "' }",
                    dataType: "json",
                    type: "POST",
                    contentType: "application/json; charset=utf-8",
                    dataFilter: function (data) { return data; },
                    success: function (data) {
                        response($.map(data.d, function (item) {
                            return {
                                name: item.Value,
                                value: item.Name
                            }
                        }))
                    }
                });
            },
            select: function (event, ui) {
                if (ui.item.name) {
                    document.getElementById("divSearchValue").innerHTML = ui.item.name;
                } 
            }
        });
    });
});

</script>


Html:

<input name="tbSearchID" type="text" id="tbSearchID" />


Web Service:

VB
<System.Web.Script.Services.ScriptService()> _
<WebService(Description:="", Name:="AIMSWebServiceProxy", Namespace:="http://aims.jocogov.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _


Public Class WebServiceProxy
    Inherits System.Web.Services.WebService
    <WebMethod()> _
    Public Function ValidateStringAjax(ByVal prefixText As String) As List(Of Results)

        'webservice: "http://ims.jocogov.org/webservices/PropertyWebService/propertywebservice.asmx?op=ValidateStringAjax"

        Dim resultsList As New List(Of Results)()
        Dim ws As New org.jocogov.ims.PropertyWebService
        Dim strLoginResult As Array
        strLoginResult = ws.ValidateStringAjax(prefixText, 25, '')

        Dim count As Integer = 0
        For Each i In strLoginResult
            count += 1
            resultsList.Add(New Results() With {.ID = 1, .Name = i.Name.ToString, .Value = i.Value.ToString, .Type = i.Type.ToString})
        Next

        Return resultsList


    End Function
End Class

C#
[System.Web.Script.Services.ScriptService()]
[WebService(Description = "", Name = "AIMSWebServiceProxy", Namespace = "http://aims.jocogov.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[Microsoft.VisualBasic.CompilerServices.DesignerGenerated()]
public class WebServiceProxy : System.Web.Services.WebService
{

	[WebMethod()]
	public List<Results> ValidateStringAjax(string prefixText)
	{
		List<Results> resultsList = new List<Results>();
		org.jocogov.ims.PropertyWebService ws = new org.jocogov.ims.PropertyWebService();
		Array strLoginResult = default(Array);
		strLoginResult = ws.ValidateStringAjax(prefixText, 25, '');

		int count = 0;
		foreach (object i_loopVariable in strLoginResult) {
			i = i_loopVariable;
			count += 1;
			resultsList.Add(new Results {
				ID = 1,
				Name = i.Name.ToString,
				Value = i.Value.ToString,
				Type = i.Type.ToString
			});

		}

		return resultsList;

	}
}

//=======================================================
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//Conversion powered by NRefactory.
//Twitter: @telerik
//Facebook: facebook.com/telerik
//=======================================================