function check_form(){   
  
    document.getElementById('error').style.display = "none";
    document.getElementById('error').innerHTML = "";
    
    var name = document.getElementById('name').value;
    var email = document.getElementById('email').value;

    if(name!="" && email!=""){
     if(checkEmailAdr(email)== true)
	 { 
	  return true;
	 }
	 else
	 {
	  document.getElementById('error').innerHTML = "Die angegebene E-mail Adresse ist nicht korrekt.";    
      document.getElementById('error').style.display = "";
	  return false;
	 }
    } 
    else 
    {
      document.getElementById('error').innerHTML = "Bitte füllen Sie alle mit einem Sternchen (*) markierten Felder aus.";    
      document.getElementById('error').style.display = ""; 
      return(false);
    }
  }
  
function checkEmailAdr( address )
  {
    var status = true;
    var username = "";
    var hostname = "";

    if ( address.length < 8 )
      return false;

    var seperate = address.lastIndexOf("@");
    if ( seperate == -1 )
      return false;

    username = address.substring(0, seperate );
    if ( ! checkUsername( username, "<>()[],;:@\" " ) )
      return false;

    hostname = address.substring(seperate+1, address.length );
    if ( ! checkHostname( hostname ) )
      return false;

    return true;
  }