Sharepoint list add item from custom form using javascript

Question

I want to add list item through custom form using asynchronous javascript but i cant able to show any message on page that item created or not

SP.SOD.executeFunc('sp.js', 'SP.ClientContext', createItem);//makes sure sp.js is loaded and then calls createListItem method
function createItem() {
    var clientContext = new SP.ClientContext.get_current();//if the page and the list are in same site.If list is in different site then use relative url instead of get_current
    var oList = clientContext.get_web().get_lists().getByTitle('Vendor');

    var itemCreateInfo = new SP.ListItemCreationInformation();
    oListItem = oList.addItem(itemCreateInfo);
    oListItem.set_item("Title", $('#RVendorDiv').val());

    oListItem.update();

    clientContext.load(oListItem);
    clientContext.executeQueryAsync(
        Function.createDelegate(oListItem, oListItem.onQuerySucceeded), 
        Function.createDelegate(oListItem, oListItem.onQueryFailed)
    );
}

function onQuerySucceeded() {
    alert('Item created successfully ' );
}

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

Answer 1

You will need to use CSOM-JS.

Refer to this post on how your HTML form should look like and this on how to do basic JavaScript operations in SharePoint 2013 or SharePoint 2010.