function validateAllSelected(){
    var unSelected_ratings = 0;
    var dropdown_value;
    var the_form = document.getElementById("form");

    var dropdowns = the_form.getElementsByTagName("select");

    for (var i = 0; i < dropdowns.length; i++) {
        dropdown_value = dropdowns[i].options[dropdowns[i].selectedIndex].value;
        if (dropdown_value == -1){
            unSelected_ratings++;
        }
    }

    if (unSelected_ratings == 0){
        alert("all dropdowns selected.");
        return true;
    }
    else{
        alert("all dropdowns are NOT selected.");
        return false;
    }
}