SharePoint 2010 JQuery Webpart

Create sharepoint blank solution
Add new webpart
Add below code in .cs file

using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;

namespace CLIENTSIDE_JQueryWebPart.JQueryDemoWebPart
{
/// <summary>
/// This Web Part renders client-side html and JavaScript that uses the jQuery
/// library. The jQuery code queries the SharePoint List Data web service to find the
/// items in the Announcements list in the intranet.contoso.com site.
/// </summary>
/// <remarks>
/// It would be easier to do this in a Visual Web Part, because instead writing code
/// in the Render() method, you could just type the markup. However, Visual Web Parts
/// cannot be used in sandbox. By building a non-visual Web Part, you can distibute
/// your Web Part as a user control.
/// </remarks>
[ToolboxItemAttribute(false)]
public class JQueryDemoWebPart : WebPart
{

protected override void CreateChildControls()
{
}
protected override void Render(HtmlTextWriter writer)
{

//First, we must render a <script> tag to link to jQuery. Because this is
//a demo, I've linked to the full version. To optimise production code, link to
//a minimised version such as jquery-1.6.3.min.js
writer.AddAttribute(HtmlTextWriterAttribute.Src,"http://ajax.microsoft.com/ajax/jquery/jquery-1.6.3.js");
writer.AddAttribute(HtmlTextWriterAttribute.Type, "text/javascript");
writer.RenderBeginTag(HtmlTextWriterTag.Script);
writer.RenderEndTag();

//Render the javascript getListItems() function
string functionJavaScript = @"
function getListItems() {
//Formulate a URL to the service to obtain the items in the Announcements list
//You must ammend this URL to match your site and list name
var Url = 'http://SERVER:9988/_vti_bin/ListData.svc/Announcements';
//call the jQuery getJSON method to get the Announcements
$.getJSON(Url, function (data) {
//Fomulate HTML to display results
var markup = 'Announcements:<br /><br />';
//Call the jQuery each method to loop through the results
$.each(data.d.results, function (i, result) {
//Display some properties
markup += 'Title: ' + result.Title + '<br />';
markup += 'ID: ' + result.Id + '<br />';
markup += 'Body: ' + result.Body + '<br />';
});
//Call the jQuery append method to display the HTML
$('#JQueryDisplayDiv').append($(markup));
//Disable HyperLink
$('#ClickHere').attr('disabled', 'disabled');
});
}";
writer.AddAttribute(HtmlTextWriterAttribute.Type, "text/javascript");
writer.RenderBeginTag(HtmlTextWriterTag.Script);
writer.Write(functionJavaScript);
writer.RenderEndTag();

//Render the display html.
//First an h2 tag
writer.RenderBeginTag(HtmlTextWriterTag.H2);

//Then a hyperlink that calls the JavaScript method
writer.AddAttribute(HtmlTextWriterAttribute.Href, "javascript:getListItems();");
writer.AddAttribute(HtmlTextWriterAttribute.Id, "ClickHere");


writer.RenderBeginTag(HtmlTextWriterTag.A);

writer.Write("Click Here to Obtain List Items");
writer.RenderEndTag();

//End the h2 tag
writer.RenderEndTag();

//Render a div to display results
writer.AddAttribute(HtmlTextWriterAttribute.Id, "JQueryDisplayDiv");
writer.RenderBeginTag(HtmlTextWriterTag.Div);
writer.RenderEndTag();
}
  }
}