How to Query SharePoint List Items Using REST and ECMA script which returns as JSON.

Here is the way you can query data from a SharePoint List by using REST and then return all these items in JSON format. You need to call these two methods with all required values. Here I am going to query a list in which "Title" column contains value 'CR' :

 This method you can call in inn your any event, where you want to access data of a SP list through REST in JSON format :

function getListItems() {

var Url = "http://<servername>:<portno>/sites/<sitename>/_vti_bin/listdata.svc/<ListName>?$filter=substringof('CR',Title)";

//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 so make sure you will get response.

function onCompletedCallback(response, eventArgs) {
//Parse the JSON reponse into a set of objects by using the JavaScript eval() function

var Items= eval("(" + response.get_responseData() + ")");
alert(Items);
//Fomulate HTML to display results
var Column1 = "Column1 : ";
var Title = "Title : ";
alert(Items.d.results.length);Column1 += 'Title: ' + Items.d.results[0]['Content'];
Title += 'Title: ' + Items.d.results[0]['Title'];

//var IDs= "IDList : ";
//var Titles = "TitleList : ";
 //for (var i = 0; i < Items.d.results.length; i++) {
//Display some properties
//Titles += 'Title: ' + Items.d.results[i]Title + ";
//IDs += 'ID: ' + Items.d.results[i].Id + ";
//}

//Display the raw JSON response
var Raw JSON response = 'Raw JSON response:' + response.get_responseData();
alert(Column1 );
alert(Title);
}

So by using this code you can get response from a list without creating so many objects(e.g. : Web, site, list, Caml Query and many more). These three alert will show Raw JSON response, Column(which can be any) and Title. Which you can customize further for use.

* Highlight 1: Its a contain filter, you can apply any as per your need. There is a very rich set of keywords there to filter.


* Highlight2: You can un comment this code and it will give you collection of items.