function moz_height(){
 if(window.innerHeight){
  document.images['hoehe_moz'].height = window.innerHeight;
 }
}

function submitform() {
 if  (document.sub_form.email_addr.value=='')
 	alert("Diese Emailadresse ist ungueltig");
 else {
  if ( ((document.sub_form.email_addr.value.indexOf('@',1))==-1)||(document.sub_form.email_addr.value.indexOf('.',1))==-1 )
  	alert("Diese Emailadresse ist ungueltig");
  else {
   document.sub_form.submit();
  }
 }
}