Edit in JSFiddle

$(document).ready(function() {
  $('#txtDate').blur(function() {
      if(validateDate('txtDate'))
      {
          alert('Date is valid');
      }
      else
      {
          alert('Invalid Date!!!');
      }
   });
});

function validateDate(txtDate){
   var txtVal = document.getElementById(txtDate).value;
   var filter = new RegExp("(0[123456789]|10|11|12)([/])([1-2][0-9][0-9][0-9])");
   if(filter.test(txtVal))
   {
      return true;
   }
   else
   {
     return false;
   }
}

Enter Date : <input type='text' id='txtDate' maxlength="7"/> (MM/YYYY)