var rollFlag = 0;

function txt_roll(str) {
    sub_num = str.substring(str.length - 2);
    sub_str = str.substring(0, str.length - 2);

    if (document.all[str].style.display == "") {
        document.all[str].style.display = "none";
        rollFlag = 0;
        return;
    }
    else {
        if (rollFlag != 0) {
            document.all[sub_str + rollFlag].style.display = "none";
            document.all[str].style.display = "";
        }

        document.all[str].style.display = "";
        rollFlag = sub_num;
    }

}