Hallo Fredi,
ganz easy ;))
<SCRIPT>
function CheckdeDat()
{
var now = new Date();
var mm = now.getMonth();
var jjjj = now.getYear();
if(jjjj<1900) jjjj+=1900;
M = new Array('Januar','Februar','März','April','Mai','Juni','Juli','August','September','Oktober','November','Dezember');
this.monat = M[mm];
if(mm==0 mm==2 mm==4 mm==6 mm==7 mm==9 mm==11) return 31;
if(mm==3 mm==5 mm==8 mm==10) return 30;
if((jjjj%4)==0 && ((jjjj%100)!=0 (jjjj%400)==0)) return 29;
return 28;
}
maxtag = CheckdeDat();
alert('der Monat '+ this.monat+' hat '+ maxtag + ' Tage');
</SCRIPT>
Viele Grüße Günter