New Post: Get Pre-Last Item in SP2010 List

Thanks for answers, All!
I have to work with the "datasheet" view because that is needed at a time to make a large number of records. (hate this)
Ok SPUpdateMultipleListItems is not for me. but i still love SPServices for his versatility 8-)
sympmarc, in accordance with your recommendation i make this:

1. On load page i get all need data in array

query_mm = "<Query>" + //my CAML with month
        "<OrderBy>" +
            "<FieldRef Name='Created' Ascending='FALSE'/>" + 
        "</OrderBy>" +
        "<Where><Eq>" +
            "<FieldRef Name='_x041c__x0435__x0441__x044f__x04'/><Value Type='Calculated'>12</Value>" + //december
        "</Eq></Where>" +
    "</Query>";

function getList(completeFunction){
    var query = query_mm;
    result = new Array();
        $().SPServices({ operation: "GetListItems", async: false, listName: "{fb58992a-4027-411e-9859-56328b461868}",CAMLQuery:query,
            completefunc: function (xData, Status) {
                $(xData.responseXML).SPFilterNode("z:row").each(function() {
                    var row = new Array();
                        row[0] = $(this).attr("ows_ID");     //id field    
                        row[1] = $(this).attr("ows_Title"); //my field for calculate
                        result[$(this).attr("ows_ID")] = row; //my array
                    }); 
                    if(completeFunction) completeFunction(result);
                }
        });

Array.prototype.clean = function(deleteValue){  //remove empty rows
    for (var i = 0; i < this.length; i++)
    {
        if (this[i] == deleteValue)
        {         
            this.splice(i, 1);
            i--;
        }
    }
    return this;
};
    result.clean(null);
    alert('Data for December: (ID/Value) '+result.join("-")); // my data may be with "reduce" i modify this values
}

after that i have "result" array with all my data. (1-10, 2-42,...etc. ID-Value)

1. With button click, I hope modify result and send in list via loop "UpdateListItems".
   If someone can help me I will be saved. How send in list array with "id-value" row.