function getUpperObj(obj, frag)
{
    do { obj = obj.parentNode; }
    while (!obj.id || eval("obj.id.search(/"+frag+"/i)<0"))
    return(obj)
}
        
function check_textarea(obj)
{
    var text = obj.value;
    var tlen = text.length;
    var tmax = obj.getAttribute("maxlength");
    if (tlen > tmax) obj.value = text.substr(0, tmax);
    getUpperObj(obj, "counter_box").getElementsByTagName("p")[0].innerHTML = "noch "+(tmax-tlen)+" von max. "+tmax+" Zeichen";
}