Solved

Complex Regular Expression for a form validation

Posted on 2013-01-05
11
1,002 Views
Last Modified: 2013-01-05
I have this form that validates with jquery & regular expressions...

...
//some code

var characterReg = /^([a-zA-Z0-9]{2,50})$/; //only letters and numbers

if ( !characterReg.test(inputValName) ){

			result.text('that\'s not a valid name!');

...
//more code

Open in new window


Now, I need a very specific validation of a field called 'NIF', wich is the identifier of a tax-paying company in my country. And I need some help to make a regular expression to use like I did in the above code.

So I found an old javascript code online that validates 'NIF':

function IsValidNIF(nif)
{
    var c;
    var checkDigit = 0;
    //Check if is not null, is numeric and if has 9 numbers
    if(nif != null && IsNumeric(nif) && nif.length == 9)
    {
        //Get the first number of NIF
        c = nif.charAt(0);
        //Check firt number is (1, 2, 5, 6, 8 or 9)
        if(c == ‘1' || c == ‘2' || c == ‘5' || c == ‘6' || c == ‘8' || c == ‘9')
        {
            //Perform CheckDigit calculations
            checkDigit = c * 9;
            var i = 0;
            for(i = 2; i <= 8; i++)
            {
                checkDigit += nif.charAt(i-1) * (10-i);
            }
            checkDigit = 11 - (checkDigit % 11);
            //if checkDigit is higher than ten set it to zero
            if(checkDigit >= 10)
                checkDigit = 0;
            //Compare checkDigit with the last number of NIF
            //If equal the NIF is Valid.            
            if(checkDigit == nif.charAt(8))
                return true;            
        }        
    }
    return false;
}

function IsNumeric(ObjVal)
{
return /^\d+$/.test(ObjVal);
}

Open in new window


So, is it possible to make a regular expression from this?

The rules are:

-must be only numbers
-must be 9 characters(numbers) long
-the first number must be 1 or 2 or 5 or 6 or 8 or 9
-the last number performs some validation(%module) that you should understand viewing the above code

Thank you.
0
Comment
Question by:joao_c
  • 5
  • 3
  • 2
  • +1
11 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 38746939
-must be only numbers
-must be 9 characters(numbers) long
-the first number must be 1 or 2 or 5 or 6 or 8 or 9
 characterReg = /^[125689][0-9]{8}$/

-the last number performs some validation(%module) that you should understand viewing the above code
This part would produce a more complicated regular expression than is worth it, so I'd stick to using code.
0
 

Author Comment

by:joao_c
ID: 38746981
What you mean " ...I'd stick to using code." ?

If possible let me know "how" complicated would the regex become. I don't mind if the regex is not "readable", the aproach of regex is just to cut some lines of code. Unless the regex could have some performance/other issues,. is that the case?

Thanks a lot.
0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 38747027
I have to agree with ozo:  You're going to be attempting to reproduce modulo arithmetic via a regex. This isn't really what regex is designed for. The code approach would be much simpler. Just use ozo's suggested pattern, then add logic for the modulo check.
0
Resolve Critical IT Incidents Fast

If your data, services or processes become compromised, your organization can suffer damage in just minutes and how fast you communicate during a major IT incident is everything. Learn how to immediately identify incidents & best practices to resolve them quickly and effectively.

 

Author Comment

by:joao_c
ID: 38747116
Thanks kaufed.

Then how would I add up the 2 things (regex + code) in my form?

Should be like:

...
//some code

var myRegex = /^[125689][0-9]{8}$/;

if ( myRegex.test(inputValName) ){

			// then implement other if here with the modulo% code??

...
//more code

Open in new window

0
 
LVL 82

Expert Comment

by:leakim971
ID: 38747124
What about :
String.prototype.ozo = function(i) { return this.charAt(i-1) * (10-i); }
function IsValidNIF(nif) {
	var checkDigit = 0;
	for(var i=1;i<9;i++) checkDigit += nif.ozo(i);
	return /^[125689][0-9]{8}$/.test(nif) && ((checkDigit%11 >= 21)?0:checkDigit == nif.charAt(8));
}

Open in new window

0
 

Author Comment

by:joao_c
ID: 38747156
Thanks for the reply leakim971.

That's a little scary for my modest understanding of jquery.

Where do I put that code in the current code I have??

	<script>


	function clearInput() {
		$("#myForm :input").each( function() {
			$(this).val('');
		});
	};



	$("#submitBtn").click( function() {


		var result = $('#result');
		var company = $('#myForm > #name-of-company');
		var ai = $('#myForm > #annual-income');
		var characterReg = /^([a-zA-Z0-9]{2,50})$/; //only letters and numbers
		var aiReg = /^([0-9]{3,15})$/; //only numbers
		var inputVal = ai.val();
		var inputValName = company.val();

		if ( !characterReg.test(inputValName) ){

			result.text('that\'s not a valid name!');
			company.addClass('wrong');
			

		} else if ( !aiReg.test(inputVal) ) {

			result.text('only numbers!');
			ai.addClass('wrong');
			company.removeClass('wrong');



		} else {

			$.post( $("#myForm").attr("action"), 
			$("#myForm :input").serializeArray(), 
			function(info){ result.html(info);
			});
			clearInput();
			company.removeClass('wrong');
			ai.removeClass('wrong');

		};


	});



	$("#myForm").submit( function() {
		return false;	
	});



	</script>

Open in new window

0
 
LVL 82

Expert Comment

by:leakim971
ID: 38747166
There's no query here. You need to replace your current function by the one provided
0
 

Author Comment

by:joao_c
ID: 38747314
but i a working with jquery here, I am more familiar with with. Don't know how to manipulate the DOM with pure js. Can I incorporate that function in my jquery?

Thanks
0
 
LVL 82

Expert Comment

by:leakim971
ID: 38747318
just replace your previous one, no more no less...
0
 
LVL 75

Accepted Solution

by:
käµfm³d   👽 earned 500 total points
ID: 38747372
Modifying your existing code:

function IsValidNIF(nif)
{
    var checkDigit = 0;
    var i = 0;
    var characterReg = /^[125689][0-9]{8}$/;
    
    if (characterReg.test(nif) {
        //Perform CheckDigit calculations
        checkDigit = nif.charAt(0) * 9;

        for(i = 2; i <= 8; i++)
        {
            checkDigit += nif.charAt(i-1) * (10-i);
        }

        checkDigit = 11 - (checkDigit % 11);

        //if checkDigit is higher than ten set it to zero
        if(checkDigit >= 10)
            checkDigit = 0;

        //Compare checkDigit with the last number of NIF
        //If equal the NIF is Valid.            
        if(checkDigit == nif.charAt(8))
            return true;
    }

    return false;
}

Open in new window


Note:  The IsNumeric shouldn't be needed anymore--at least not for this function.
0
 

Author Closing Comment

by:joao_c
ID: 38748118
Thank you, it works great.
0

Featured Post

Guide to Performance: Optimization & Monitoring

Nowadays, monitoring is a mixture of tools, systems, and codes—making it a very complex process. And with this complexity, comes variables for failure. Get DZone’s new Guide to Performance to learn how to proactively find these variables and solve them before a disruption occurs.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Nothing in an HTTP request can be trusted, including HTTP headers and form data.  A form token is a tool that can be used to guard against request forgeries (CSRF).  This article shows an improved approach to form tokens, making it more difficult to…
The Windows functions GetTickCount and timeGetTime retrieve the number of milliseconds since the system was started. However, the value is stored in a DWORD, which means that it wraps around to zero every 49.7 days. This article shows how to solve t…
In this seventh video of the Xpdf series, we discuss and demonstrate the PDFfonts utility, which lists all the fonts used in a PDF file. It does this via a command line interface, making it suitable for use in programs, scripts, batch files — any pl…
In a recent question (https://www.experts-exchange.com/questions/29004105/Run-AutoHotkey-script-directly-from-Notepad.html) here at Experts Exchange, a member asked how to run an AutoHotkey script (.AHK) directly from Notepad++ (aka NPP). This video…

749 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question