working with ECMA script in SharePoint

The following example displays the ID, in addition to the Title and Body column values, of the first 100 items in the Announcements list, starting with list items whose collection ID is greater than 10.

function retrieveListItems() {

    var clientContext = new SP.ClientContext(siteUrl);
    var oList = clientContext.get_web().get_lists().getByTitle('Announcements');
        
    var camlQuery = new SP.CamlQuery();
    camlQuery.set_viewXml('<View><Query><Where><Geq><FieldRef Name=\'ID\'/>' + 
        '<Value Type=\'Number\'>1</Value></Geq></Where></Query><RowLimit>10</RowLimit></View>');
    this.collListItem = oList.getItems(camlQuery);
        
    clientContext.load(collListItem);
        
    clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));        
        
}

function onQuerySucceeded(sender, args) {

    var listItemInfo = '';

    var listItemEnumerator = collListItem.getEnumerator();
        
    while (listItemEnumerator.moveNext()) {
        var oListItem = listItemEnumerator.get_current();
        listItemInfo += '\nID: ' + oListItem.get_id() + 
            '\nTitle: ' + oListItem.get_item('Title') + 
            '\nBody: ' + oListItem.get_item('Body');
    }

    alert(listItemInfo.toString());
}

function onQueryFailed(sender, args) {

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

ECMScript 



ECMScript you need to create a client context before you can retrieve data from a SharePoint site.



With ECMAScript you can retrieve the client context from the SharePoint site in which the script runs.

Use the Load method to specify which data to load from SharePoint.



Use the asynchronous method executeQueryAsync to retrieve the information from SharePoint. This method needs a reference to a callback method when the execution succeeds and a reference to a callback method when the execution fails.



To Set and Get the Properties there are ways to get the information.



get_methodname
set_Methodname


example get_web(), set_title etc


Update, Insert, Delete Code snippets 

1. Load Site Data  

<script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
clientContext.load(web, 'Title');
clientContext.executeQueryAsync(Function.createDelegate(this, this.onSiteLoadSuccess), Function.createDelegate(this, this.onQueryFailed));
}
function onSiteLoadSuccess(sender, args) {
 alert("site title : " + web.get_title());
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​

2.Load List Items Data  

 <script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
var list = web.get_lists().getByTitle("Pages");
var camlQuery = new SP.CamlQuery();
var q = '<View><RowLimit>5</RowLimit></View>';
camlQuery.set_viewXml(q);
this.listItems = list.getItems(camlQuery);
clientContext.load(listItems, 'Include(DisplayName,Id)');
clientContext.executeQueryAsync(Function.createDelegate(this, this.onListItemsLoadSuccess),
Function.createDelegate(this, this.onQueryFailed));
}
function onListItemsLoadSuccess(sender, args) {
 var listEnumerator = this.listItems.getEnumerator();
 //iterate though all of the items
 while (listEnumerator.moveNext()) {
     var item = listEnumerator.get_current();               
     var title = item.get_displayName();
     var id = item.get_id();
            alert("List title : " + title + "; List ID : "+ id);
        }
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​ 

3. Load List Data 

<script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
this.list = web.get_lists().getByTitle("Images");
clientContext.load(list, 'Title', 'Id');
clientContext.executeQueryAsync(Function.createDelegate(this, this.onListLoadSuccess),
Function.createDelegate(this, this.onQueryFailed));
}
function onListLoadSuccess(sender, args) {
 alert("List title : " + this.list.get_title() + "; List ID : "+ this.list.get_id());
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​

4.  Create List 

<script type="text/javascript">

var clientContext = null;
var web = null;

ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");

function Initialize()
{

clientContext = new SP.ClientContext.get_current();

web = clientContext.get_web();

var itemCreateInfo = new SP.ListItemCreationInformation();

var listCreationInfo = new SP.ListCreationInformation();

listCreationInfo.set_title('My Custom Generic List');

listCreationInfo.set_templateType(SP.ListTemplateType.genericList);

this.oList = web.get_lists().add(listCreationInfo);

clientContext.load(oList, 'Title', 'Id');

clientContext.executeQueryAsync(Function.createDelegate(this, this.onListCreateSuccess),

Function.createDelegate(this, this.onQueryFailed));

}

function onListCreateSuccess(sender, args) {
 alert("List title : " + this.oList.get_title() + "; List ID : "+ this.oList.get_id());
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}

</script>​ 

5. Create Site 

 <script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
var webCreateInfo = new SP.WebCreationInformation();
    webCreateInfo.set_description("All about Rare solutions.");
    webCreateInfo.set_language(1033);
    webCreateInfo.set_title("Rare Solutions - SharePoint and .NET");
    webCreateInfo.set_url("RareSolutionsSharePoint");
    webCreateInfo.set_useSamePermissionsAsParentSite(true);
    webCreateInfo.set_webTemplate("BLOG#0");

    this.oNewWebsite = this.web.get_webs().add(webCreateInfo);

    clientContext.load(this.oNewWebsite, 'ServerRelativeUrl', 'Created');

clientContext.executeQueryAsync(Function.createDelegate(this, this.onCreateWebSuccess),

Function.createDelegate(this, this.onQueryFailed));
}
function onCreateWebSuccess(sender, args) {
 alert("Web site url : " + this.oNewWebsite.get_serverRelativeUrl());
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​ 

6. Update List 

<script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
this.list = web.get_lists().getByTitle('My custom generic list');
list.set_description('My custom generic list description');
list.update();
clientContext.load(list, 'Description');
clientContext.executeQueryAsync(Function.createDelegate(this, this.onSiteLoadSuccess), Function.createDelegate(this, this.onQueryFailed));
}
function onSiteLoadSuccess(sender, args) {
 alert("list description : " + this.list.get_description());
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​


7.  Update List Item


<script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
this.list = web.get_lists().getByTitle('My custom generic list');
this.oListItem = list.getItemById(1);
oListItem.set_item('Title', 'Praveen Battula Updated');
oListItem.update();

clientContext.executeQueryAsync(Function.createDelegate(this, this.onUpdateListItemSuccess), Function.createDelegate(this, this.onQueryFailed));
}
function onUpdateListItemSuccess(sender, args) {
 alert("list item updated");
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​

8. Delete List 

<script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
this.list = web.get_lists().getByTitle('My custom generic list');
list.deleteObject();

clientContext.executeQueryAsync(Function.createDelegate(this, this.onListDeleteSuccess),

Function.createDelegate(this, this.onQueryFailed));
}
function onListDeleteSuccess(sender, args) {
 alert("list deleted");
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​

 9. Delete Site 

<script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
this.website = web.get_webs().getByTitle('Rare Solutions');
website.deleteObject();

clientContext.executeQueryAsync(Function.createDelegate(this, this.onSiteDeleteSuccess),

Function.createDelegate(this, this.onQueryFailed));
}
function onSiteDeleteSuccess(sender, args) {
 alert("site deleted");
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​

10. Delete List Item 

<script type="text/javascript">
var clientContext = null;
var web = null;
ExecuteOrDelayUntilScriptLoaded(Initialize, "sp.js");
function Initialize()
{
clientContext = new SP.ClientContext.get_current();
web = clientContext.get_web();
this.list = web.get_lists().getByTitle('My custom generic list');
this.oListItem = list.getItemById(1);
oListItem.deleteObject();

clientContext.executeQueryAsync(Function.createDelegate(this, this.onListItemDeleteSuccess),

Function.createDelegate(this, this.onQueryFailed));
}
function onListItemDeleteSuccess(sender, args) {
 alert("list item deleted");
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}</script>​

Source :----click Here and  Here