Get JSON response for SharePoint list items with Client Object model

Here is working Example for Retrieving SharePoint list items to get JSON response with Client Object model.

<script type=”text/javascript”>

//This functions makes the request to the RESTful ListData service
function getListItems() {

var Url = “http://Spsite/_vti_bin/ListData.svc/Announcements”;

//Create a WebRequest object
var request = new Sys.Net.WebRequest();

//Specify the verb
request.set_httpVerb(“GET”);

//Use the URL we already formulated
request.set_url(Url);

//Set the Accept header to ensure we get a JSON response
request.get_headers()["Accept"] = “application/json”;

//Add a callback function that will execute when the request is completed
request.add_completed(onCompletedCallback);

//Run the web requests
request.invoke();
}

//This function runs when the web request completes

function onCompletedCallback(response, eventArgs) {
//Parse the JSON reponse into a set of objects by using the JavaScript eval() function
var announcements = eval(“(” + response.get_responseData() + “)”);

//Fomulate HTML to display results
var markup = “Announcements:”;

for (var i = 0; i < announcements.d.results.length; i++) {
//Display some properties
markup += ‘Title: ‘ + announcements.d.results[i].Title + ”;
markup += ‘ID: ‘ + announcements.d.results[i].Id + ”;
markup += ‘Body: ‘ + announcements.d.results[i].Body + ”;
}

//Display the raw JSON response
markup += “Raw JSON response:” + response.get_responseData();

//Update the displayDiv
displayDiv.innerHTML = markup;
}

</script>

<a href=”javascript:getListItems()”>Click Here to Obtain List Items</a>