function validate_keystroke(e, sType) {

    // only allow valid keystrokes into the fields

    var key;
    var keychar;
    var reg;

    if (window.event) {
        // for IE, e.keyCode or window.event.keyCode can be used
        key = e.keyCode;
    }
    else if (e.which) {
        // netscape
        key = e.which;
    }
    else {
        // no event, so pass through
        return true;
    }

    keychar = String.fromCharCode(key);

    if (sType == 'number') {
        reg = /(^[\d]?$)/;
    }
    else if (sType == 'numbercsv') {
        reg = /(^[\d\,]?$)/;
    }
    else if (sType == 'decimal') {
        reg = /(^[\d\.]?$)/;
    }
    else {
        reg = /(^[\d\.]?$)/;
    }

    var rtn = reg.test(keychar);

    return rtn;

}