[Javascript] Regarding Password Validation

[Håkan Magnusson]

> On the regular expression you suggested, each part (numbers,
> meta-characters) are in fact represented, but the way I'd interpret this is
> 2 or more digits followed by 1 or more meta-characters -- and nothing else.

As I wrote, "something that vaugely resembles this line should probably 
work:", I did not write "this is the ultimate solution to all your 
password validation problems". There are a few things missing in my 
regexp, but not much at all.


> Trying to write "OR'd" terms into a regex covering every possible
> permutation would take too much brain power (and I have little enough to
> spare at present).  It would also make the expression rather lengthy, and
> hard to manage.

This is, as I said earlier, not true. It is very, very simple to check 
for one or more needles in a haystack via regular expressions, in any 
order. I've never seen a scenario where you actually would have to use 
two regexps for this kind of simple operation.


> The method I suggested is certainly less elegent, but (a)
> much faster

Much faster? Ahem?
Explain to me how executing two regexp checks and two conditional checks 
can be (much) faster than one regexp check and one conditional check.


> and (b) easier to make sense of.

This is quite a contradiction you're presenting here, I must say that I 
am confused. First, you say that if you don't know regexp you're missing 
out on 80% of the powers of JavaScript, and in your next mail, you 
suggest that writing regexp code that does half the work but looks 
'good' (to who?) is better than writing regexp code that does all the 
work in one line, and looks correct.

I'm not utterly convinced, so to say.

H

David Lovering wrote:

> On the regular expression you suggested, each part (numbers,
> meta-characters) are in fact represented, but the way I'd interpret this is
> 2 or more digits followed by 1 or more meta-characters -- and nothing else.
> Any additional characters, or when the numbers and meta characters do not
> appear consecutively in this fashion would cause the expression to evaluate
> "false".
> 
> Trying to write "OR'd" terms into a regex covering every possible
> permutation would take too much brain power (and I have little enough to
> spare at present).  It would also make the expression rather lengthy, and
> hard to manage.  The method I suggested is certainly less elegent, but (a)
> much faster, and (b) easier to make sense of.
> 
> -- Dave Lovering
> 
> ----- Original Message ----- 
> From: "Ramachandran" <ramachandran at summitworks.com>
> To: "[JavaScript List]" <javascript at LaTech.edu>
> Sent: Monday, March 01, 2004 8:45 AM
> Subject: RE: [Javascript] Regarding Password Validation
> 
> 
> 
>>Hi Hakan,
>>
>>Yes i really need the Regular Expression for these conditions. If u find
>>time...please write and send it to me...
>>
>>
>>
>>-----Original Message-----
>>From: javascript-bounces at LaTech.edu
>>[mailto:javascript-bounces at LaTech.edu]On Behalf Of Hakan Magnusson
>>Sent: Monday, March 01, 2004 9:06 PM
>>To: [JavaScript List]
>>Subject: Re: [Javascript] Regarding Password Validation
>>
>>
>>Ramachandran,
>>This could be accomplished with only one regexp, of course.
>>
>>My regexp skills are not quite up to date, but something that vaugely
>>resembles this line should probably work:
>>
>>/[0-9]{2,}[^a-zA-Z0-9]{1,}/
>>
>>You can then test your password field value against the regexp, and it
>>will return true if the password has at least two numbers and one
>>special character.
>>
>>Again, my regexp skills are not very hot. Someone who do know the ins
>>and outs of regexps can build this for you in the blink of an eye, this
>>regexp is NOT complicated. If you really need me to, I can build it for
>>you when I have the time.
>>
>>Dave,
>>I don't know about 'missing 80% of the power of JavaScript', regexps
>>have nothing to do with JavaScript. Saying that someone who doesn't know
>>regexps are missing 80% of the power of string manipulation/testing
>>sounds more accurate to me. ;)
>>
>>H
>>
>>
>>David Lovering wrote:
>>
>>
>>>The easiest way I can think of is to use two regular expression filters
> 
> to
> 
>>>strip (respectively) everything out EXCEPT numbers, and everything out
>>>EXCEPT special characters.  The output of these two filters are put into
>>
>>two
>>
>>>strings, such as
>>>
>>>var digitString;
>>>var specialString;
>>>
>>>... and then simply check the length of the two strings to make sure
> 
> that
> 
>>>they are greater than or equal to 2 and 1, again respectively.
>>>
>>>If you're not up on regular expression filters, you're missing about 80%
>>
>>of
>>
>>>the power of JavaScript (at least IMO).
>>>
>>>Try
>>>
>>>  var re0 = /[^0-9]/g;
>>>  var re1 = /[a-zA-Z0-9]/g;
>>>
>>>  var digitString = myString.replace(re0, "");
>>>  var specialString = myString.replace(re1, "");
>>>
>>>  alert("number of digits: " + digitString.length);
>>>  alert("number of special characters: " + specialString.length);
>>>
>>>Or some variation thereof.  Incidently, I'd also check myString (the
>>
>>target
>>
>>>string coming in) for total length as well, as short strings are easy to
>>>crack.
>>>
>>>-- Dave Lovering
>>>----- Original Message -----
>>>From: "Ramachandran" <ramachandran at summitworks.com>
>>>To: "[JavaScript List]" <javascript at LaTech.edu>
>>>Sent: Monday, March 01, 2004 6:42 AM
>>>Subject: [Javascript] Regarding Password Validation
>>>
>>>
>>>
>>>
>>>>Hi all,
>>>>
>>>>I want to perform a validation in password field. The validation
> 
> includes
> 
>>>>the following conditions.
>>>>
>>>>1. It should contain atleast two no.s and once special characters.
>>>>
>>>>How can i do this one..
>>>>
>>>>Regards,
>>>>Ram
>>>>
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>>>>
>>>>
>>>
>>>
>>>
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>>>
>>
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>>
> 
> 
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