function validate_form(formtype) 
{
  validity = true; // assume valid

  message="";

  if (!check_empty(document.form.NAME.value))
  {
  	validity = false; 
  	message = message + "field NAME is empty!\n";
  }

  if (!check_empty(document.form.TELEFON.value))
  { 
    validity = false;  
  	message = message + "field PHONE is empty!\n";
  }

  if (!check_email(document.form.EMAIL.value))
  { 
  	validity = false; 
  	message = message + "eMail is not valid!\n";
  }

  if (!check_empty(document.form.MITTEILUNG.value))
  {
  	validity = false; 
  	message = message + "Notes are empty!\n";
  }

  if(formtype == "scanE")
  {
    // Berechne Summe der Scans
    summe = ((document.form.MENGEA2.value=="") ? 0 : (parseInt(document.form.MENGEA2.value))) +
            ((document.form.MENGEA3.value=="") ? 0 : (parseInt(document.form.MENGEA3.value))) +
            ((document.form.MENGEA4.value=="") ? 0 : (parseInt(document.form.MENGEA4.value))) +
            ((document.form.MENGEA5.value=="") ? 0 : (parseInt(document.form.MENGEA5.value))) +
            ((document.form.MENGEA6.value=="") ? 0 : (parseInt(document.form.MENGEA6.value)));

    if (isNaN(summe))
    {
  	  validity = false; 
  	  message = message + "Please fill in a number of scans!\n";
    }

    if (summe == 0)
    {
    	validity = false; 
    	message = message + "The amount of scans is 0!\n";
    }
  }

  if(formtype == "plot")
  {
    summe = parseInt(document.form.ANZAHL.value);
            
    if (isNaN(summe))
    {
    	validity = false; 
    	message = message + "Please fill in a number of plots!\n";
    }

    if (summe == 0)
    {
    	validity = false; 
    	message = message + "The number is 0!\n";
    }
  }
  <!--
  //if (!document.form.AGB.checked)
  //{
  //	validity = false; 
  //	message = message + "Bitte AGBs akzeptieren!\n";
  //}

  if (!validity)
  {
    alert(message);
  }
   
  //	if (validity)
  //	{
  //	  alert("All informations are checkedand ok.");
  //	}
  return validity;
}


function check_empty(text) 
{
  return (text.length > 0); // gibt false zurück wenn leer
}


function check_email(address) 
{
  if ((address == "") || (address.indexOf ('@') == -1) || (address.indexOf ('.') == -1))
  {
    return false;
  }
    
  return true;
}