function validate_required(field,alerttxt)
{
  with (field)
  {
    if (value==null||value=="")
    {
      alert(alerttxt);
      return false;
    } else {
      return true;
    }
  }
}

function IsNumeric(sText)
{
  var ValidChars = "0123456789";
  var IsNumber=true;
  var Char;

  for (i = 0; i < sText.length && IsNumber == true; i++) 
  { 
    Char = sText.charAt(i); 
    if (ValidChars.indexOf(Char) == -1) 
    {
      IsNumber = false;
    }
  }
  return IsNumber;
 }


function validate_form(thisform)
{
  with (thisform)
  {
    if (validate_required(name,"Please fill in your name!")==false)
    {
      name.focus();
      return false;
    } else if (validate_required(email,"Please fill in your Email Address!")==false)
    {
      email.focus();
      return false;
    } else if (validate_required(hphone,"Please fill in your Mobile Number!")==false)
    {
      hphone.focus();
      return false;
    } else if (IsNumeric(hphone.value)==false) 
    {
      alert("Please fill in with numbers only without dash or bracket!");
      hphone.focus();
      return false;
    } 
    else {
      window.location = "thankyou.html";
    }
  }
}