Regular Expression form field validation

[FattiFat]

Hi Everyone,
I need to add a form field validation using Javascript to make sure a text field's value is entered correctly. I lack expertise in this field, so all of this Javascript code is looking like a different language to me...

What I need is to validate the field so that it is the following pattern "mmyy" (basically a 4 digit numeric value). I was thinking that function validateValue is the way to go - but I am unsure how to write the rest. Can anyone help me out?

[JavaServlet]

Originally Posted by FattiFat

Hi Everyone,
I need to add a form field validation using Javascript to make sure a text field's value is entered correctly. I lack expertise in this field, so all of this Javascript code is looking like a different language to me...

What I need is to validate the field so that it is the following pattern "mmyy" (basically a 4 digit numeric value). I was thinking that function validateValue is the way to go - but I am unsure how to write the rest. Can anyone help me out?

Here is one way to do it using test method. I also included a replace method to trim the value.

function validater(fld) {
  var fourDigits = /^\d{4}$/;
  var formValue = document.demo.monthYear.value;
  var trimmed = formValue.replace(/^\s+|\s+$/g, '');

  if (fourDigits.test(trimmed))
  {
    alert("Four Digits");
  }
  else
  {
    alert("Not four digits.");
  } 
  return false; 
}

[FattiFat]

Awesome! That is what I needed. Thanks.

[FattiFat]

One more question......

Is there anyway to specify that the digits must meet a certain criteria? For example, since this is for an expiration date, I do not want someone to enter a month and date that has already passed.

Can this be done in the expression or would I need some additional Javascript coding to validate the field?

[unigogo]

need some additional Javascript coding