function $(x){return document.getElementById(x)}
szam=25;
ie=(navigator.appName=='Microsoft Internet Explorer')?1:0;
function as(e){
if(ie){x2=1}
else{if(e.which=='8'){x2=0}else{x2=1}}
if($('dolog').value.length>=szam && x2){
if(ie){event.returnValue=false}
return false;
}
return true;
}
function bs(){$('dolog').value=$('dolog').value.slice(0,szam);cs();}
function cs(){innerHTML=szam-$('dolog');}
function main(){
setInterval('bs();',500);
$('dolog').onkeyup=dolog.value = dolog.value.replace(/[^A-Za-z0-9\s_():.αιϋϊυσόφνΦάΣΪΥΫΑΙΝ+-=]/g, '');
$('dolog').onkeypress=as;
}