ECMAScript Crud operation in SharePoint 2013

$(document).ready( function(){

$("#btnSave").click(function(){ AddListItem();} );


$("#btnUpdate").click(function(){ UpdateListItem();} );


$("#btnDelete").click(function(){

alert('Delete button is clicked ...!!!!');
DeleteListItem1();} );
}

);







function AddListItem(){
alert('AddListItem called ..!!');

    var ListName = "TestList";
    var context = new SP.ClientContext.get_current(); // the current context is taken by default here
    //you can also create a particular site context as follows
    //var context = new SP.ClientContext('/Sites/site1');
    var lstObject = context.get_web().get_lists().getByTitle(ListName);
    var listItemCreationInfo = new SP.ListItemCreationInformation();
    var newItem = lstObject.addItem(listItemCreationInfo);
    newItem.set_item('Title', 'This is new item');
    // set values to other columns of the list here
    newItem.update();
   
    alert('Hi...');
   
//context.executeQueryAsync(Function.createDelegate(this, this.onAddSuccess),Function.createDelegate(this, this.onAddFailure));

context.executeQueryAsync( function onAddSuccess() { alert('Item created: ' + newItem.get_id());} , Function.createDelegate(this, this.onAddFailure));


   
 }
     function onAddSuccess() { alert('Item created: ' + newItem.get_id());}

    function onAddFailure(sender, args) {

        alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
    }











function UpdateListItem()
{
var ListName = "TestList";
var context = new SP.ClientContext.get_current(); // the current context is taken by default here
//you can also create a particular site context as follows
//var context = new SP.ClientContext('/Sites/site1');

var lstObject = context.get_web().get_lists().getByTitle(ListName);
this.lstObjectItem = lstObject.getItemById(75);
lstObjectItem.set_item('Title', 'This is updated item');
lstObjectItem.update();
lstObject.set_description("Updated description using ECMAScript");
lstObject.update();
context.executeQueryAsync(Function.createDelegate(this, this.onUpdateSuccess),
Function.createDelegate(this, this.onUpdateFailure));
}

function onUpdateSuccess() {
alert('Item udated');
}

function onUpdateFailure(sender, args) {
alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}







function DeleteListItem1()
{
alert('Delete function is callaed ...!!');

var ListName = "TestList";
var context = new SP.ClientContext.get_current(); // the current context is taken by default here
//you can also create a particular site context as follows
//var context = new SP.ClientContext('/Sites/site1');

var lstObject = context.get_web().get_lists().getByTitle(ListName);
this.lstObjectItem = lstObject.getItemById(75);
lstObjectItem.deleteObject();

context.executeQueryAsync(Function.createDelegate(this, this.onSuccess),
Function.createDelegate(this, this.onFailure));
}

function onSuccess() {
alert('Item Deleted');
}

function onFailure(sender, args) {
alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}