Fetching Data from Folder

        function retrieveListItems() {
            var clientContext = new SP.ClientContext.get_current();
            var oList = clientContext.get_web().get_lists().getByTitle('List Name');
            var camlQuery = new SP.CamlQuery();
         
            camlQuery.set_viewXml('<View><Query><Where><Eq><FieldRef Name=\'Reference_x0020_Id\'/><Value Type=\'Text\'>' + document.getElementById('txtReferenceId').value + '</Value></Eq></Where></Query></View>');
            camlQuery.set_folderServerRelativeUrl(URL);

            this.collListItem = oList.getItems(camlQuery);
            clientContext.load(collListItem);
            clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));
        }
         function onQuerySucceeded(sender, args) {
       
        }
        function onQueryFailed(sender, args) {
            alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
        }