Javascript Exception

The throw statement interrupts execution of the function. It should be given an exception object containing a name property that identifies the type of the exception, and a descriptive message property. You can also add other properties.

function UserException(message) {   this.message = message;   this.name = "UserException";}function getMonthName(mo) {   mo = mo-1; // Adjust month number for array index (1=Jan, 12=Dec)   var months = new Array("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",      "Aug", "Sep", "Oct", "Nov", "Dec");   if (months[mo] !== undefined) {      return months[mo];   } else {      throw new UserException("InvalidMonthNo");   }} try {   // statements to try   var myMonth = 15; // 15 is out of bound to raise the exception   monthName = getMonthName(myMonth);} catch (e) {   monthName = "unknown";   logMyErrors(e.message, e.name); // pass exception object to err handler}