var table,
    table_trs,
    table_tds,
    table_tds_filtered,
    message;

var cache = function() {
    message = '';
    table = $("table");
    table_trs = table.find("tr");
    table_tds = table_trs.find("td");
    table_tds_filtered = table_tds.filter(function(i,el){
        return $(el).css("color") !== $(el).css("background-color");
    });
}

var composeMessage = function() {
    table_tds_filtered.each(function(){
        message += $(this).text();
    });
}

function solution() {
    cache();
    composeMessage();
    return message;
}