<td>Credit Card Expiration Date</td><td>:<input class="input" type="text" name="CC_expiration_date" id="CC_expiration_date"><p>(MM/YY)</p></td>

/^(d{2})[-/](d{2})[-/](d{4})$/.exec(date);

function validDate(dValue) {
  var result = false;
  dValue = dValue.split('/');
  var pattern = /^d{2}$/;

  if (dValue[0] < 1 || dValue[0] > 12)
      result = true;

  if (!pattern.test(dValue[0]) || !pattern.test(dValue[1]))
      result = true;

  if (dValue[2])
      result = true;

  if (result) alert("Please enter a valid date in MM/YY format.");
}

var s = "11/12";
/^(0[1-9]|1[0-2])/d{2}$/.test(s);

var d = "09/11"
var pattern = /^(0[1-9]|1[012])/d{2}$/
pattern.test(d)