function validate_email(field,alerttxt)
{
with (field)
  {
  apos=value.indexOf("@");
  dotpos=value.lastIndexOf(".");
  if (apos<1||dotpos-apos<2)
    {alert(alerttxt);return false;}
  else {return true;}
  }
}

function validate_form(theForm)
{
  if (theForm.name.value == "")
  {
    alert("Please insert your name.");
    theForm.name.focus();
    return (false);
  }
  var alphaExp = /^[a-zA-Z\ ]+$/;
	if (theForm.name.value.match(alphaExp))
	{true;}
	else
	{ alert("Please use English letters only.");
    theForm.name.focus();
    return (false);
	  }
   if (theForm.email.value == "")
  {
    alert("Please insert your e-mail.");
    theForm.email.focus();
    return (false);
  }    
 with (theForm)
  {
  if (validate_email(email,"This is not a correct e-mail address. Please correct.")==false)
    {email.focus();return false;}
  }  
   
 if (theForm.phone.value == "")
  {
    alert("Please insert your phone number.");
    theForm.phone.focus();
    return (false);
  }

   if (theForm.phone.value.length < 8)
  {
    alert("Please insert at least 8 figures. Don't forget your area / dialling code.");
    theForm.phone.focus();
    return (false);
  }
 var numericExpression = /^[0-9\/ _\-\*\(\)]+$/;
	if (theForm.phone.value.match(numericExpression))
	{true;}
	else
	{ alert("Please insert figures only.");
    theForm.phone.focus();
    return (false);
	  }
}