# Validate CF7 textfield with 11 check for Dutch BSN

I'm using CF7 on a Wordpress website and would like to validate a textfield if it contains 9 digits and with the so called 11-check. That's an algorithm to validate Dutch SSN (BSN).

It works likes this:

Let's say we perform the 11-check on BSN 123456782

1st digit = 1, 9 * 1 = 9

2nd digit = 2, 8 * 2 = 16

3rd digit = 3, 7 * 3 = 21

4th digit = 4, 6 * 4 = 24

5th digit = 5, 5 * 5 = 25

6th digit = 6, 4 * 6 = 24

7th digit = 7, 3 * 7 = 21

8th digit = 8, 2 * 8 = 16

9th digit = 2, -1 * 2 = -2 (last digit is not added but subtracted)

Total is 154

Because 154 can be divided by 11 and it's a 9 digit number we can assume it is a valid BSN (154/11=14). It's important that there also is a validation of the length of 9 digits and that it's only possible to enter digits.

I think this can be done with Javascript.

The validation should work like any other validation in Contact Form 7. So that the form cannot be submitted when the input is invalid.

Evner: PHP, WordPress, jQuery

Om arbejdsgiveren:
( 0 bedømmelser ) Hoogerheide, Netherlands

Projekt ID: #29467860

## Tildelt til:

akhileshsharma09

Hi, I have read the task description and understood your algo and i am pretty confident that i can do this job. I have done many customizations and validations to CF7 before as well. So let's talk in chat for more deta Flere

€30 EUR på 1 dag
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## 6 freelancere byder i gennemsnit €40 timen for dette job

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asiflak

✔️ Hey There, 5 years experienced Wordpress gurru is here to assist you in this project. I have gone through your project description and I am fully confident to deliver a satisfied job. ✅ Here are some examples of my Flere

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xWordpress

Hi, i can make your project " Validate CF7 textfield with 11 check for Dutch BSN " i'm available. I have big experience in PHP, jQuery and WordPress . Please contact me and i start the project right now!

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AleksandarDikic

Hi, I am a fullstack web developer and a PHP expert. I read the description carefully and I am sure I can do the job very well. As a seasoned PHP developer I have the following skills: - Profound knowledge of Ajax, j Flere

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davronbekvssatto

Hi Thanks for job posting and I read your description carefully. I hope work with you because my skill set is very suitable to your Job and i can start now. I am confident to finish project before deadline and to handl Flere

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