function onlyLetters(e)
{
   var no_numbers = new RegExp('[A-Z\u0008\u000E\u000F\u002E\u0025\u0027\u0009]');
   var keyNum;
   var keyChar;
   
   if(window.event)
      keyNum = e.keyCode;
   else if(e.which)
      keyNum = e.which;
      
   keyChar = String.fromCharCode(keyNum);
   
   return no_numbers.test(keyChar);
}

function onlyNumbers(e)
{
   var no_letters = new RegExp('[a-i0-9\u0008\u002E\u0025\u0027\u0009\u0060]');
   var keyNum;
   var keyChar;
   
   if(window.event)
      keyNum = e.keyCode;
   else if(e.which)
      keyNum = e.which;
      
   keyChar = alert(String.fromCharCode(keyNum));
   
   return no_letters.test(keyChar);
}

function checkEmail()
{
   var email_pattern = new RegExp("^[_a-zA-Z0-9-]+(\.[_a-zA-Z0-9-]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)*\.(([0-9]{1,3})|([a-zA-Z]{2,3})|(info))$");
   
   if(email_pattern.test(document.getElementById("email").value) == false)
      document.getElementById("email").value = "\u0000";
}

function checkRequired()
{
   
   if(document.getElementById("first").value.length >= 3 && document.getElementById("last").value.length >= 3 && document.getElementById("area").value.length == 3 && document.getElementById("prefix").value.length == 3 && document.getElementById("suffix").value.length == 4)
      document.getElementById("submit").disabled = false;
   else
      document.getElementById("submit").disabled = true;
}