need to apply css for mouseover text

Question

I have written the following snippet for displaying mouseover over a image but i wont to apply css for the text which is being displayed on mouseover.

$(document).delegate("#fileGrid .objbox table tbody tr td","mouseover", function() {
    var id = $(this).attr('id').split("_");
    var rowId = id[1];
    var columnId = id[2];
    switch(columnId) {
    case "3":
        var imgSource = tradingPartnerGrid.cells(rowId, columnId).getValue();
        var imgVal =imgSource.indexOf("closure.png");
        if(imgVal!=-1){
            $(this).css("cursor", "pointer");
            var title = $("#closureIndicatorReason").html();
            $(this).attr('title', title);
        }
        break;
    }
});