List Item creation in SharePoint hosted App using REST

Hi, 

I am trying to create list item in SharePoint Hosted app using REST api. Below is my code in App.js:

function createItem() {

    var listUrl = _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getbytitle('List1')/items";
    //alert(listUrl);
    requestDetails = {
        "__metadata": { "type": "SP.Data.List1ListItem" },
        "Title" : "NoTitle",
       
    };

    actualData = JSON.stringify(requestDetails);
    requestHeaders = {
        "accept": "application/json;odata=verbose",
        "contentType": "application/json;odata=verbose",
        "X-RequestDigest": $("#__REQUESTDIGEST").val(),
    };

    $.ajax({
        url: listUrl,
        method: "POST",
        headers: requestHeaders,
        data: actualData,
        success: createdsuccessfully(),
        error: alert("creation failed")

    });
}

function listLink() {
    var link = document.getElementById("listLink");
    var clickurl = spAppWebUrl + "/lists/List1/AllItems.aspx";
    link.setAttribute("href", clickurl);

}

function createdsuccessfully() {

    alert("Item created");
}

The target list(List1) is in appweb and app permission is set to web(scope) write permission. This is never creating list item and calling both success and error method of $.ajax.

I am  not sure what is wrong here. List contains only one column i.e. Title and I am trying to create new Title value i.e. NoTitle.

Please help.