ECMA Script to fetch data from List

<script  type="text/javascript">

SP.SOD.executeOrDelayUntilScriptLoaded(retrieveListItems, 'SP.js');// It will execute after

function retrieveListItems() {

var clientContext =  new SP.ClientContext.get_current();

var oList = clientContext.get_web().get_lists().getByTitle('Test Data');

var camlQuery = new SP.CamlQuery();

camlQuery.set_viewXml('<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 listItemEnumerator = collListItem.getEnumerator();

    while (listItemEnumerator.moveNext()) {

    var oListItem = listItemEnumerator.get_current();

       oListItem.get_item('YTD');             

    }

}

</script>