//Instant Validation with JavaScript-enabled WebDB
  //Listing 1

  //The JavaScript function isDate checks whether the text entered in a field has 
  //the date format MM/DD/YYYY, displaying an error message and returning a value 
  //of “false” if it does not.

isDate
function isDate(theElement, theName)
{
// This function checks if the text entered in a field 
// has the format MM/DD/YYYY. 
// Only the format is checked, not the date itself.

 var date_regex = /^\d{1,2}\/\d{1,2}\/\d{4}$/;

// ^ indicates start of expression
// \d{1,2} - the \d means digits and {1,2} means 1 or 2 digits
// $ indicates end f expression

 if (!date_regex.test(theElement.value))
 {
  alert(theName + ": " + theElement.value + " is NOT a valid date");
  theElement.focus();
  return(false);
 }

 return(true);
}