digittwo

Thank you for your help with this.

We have now achieved the desired effect.

One last thing is it possible that once the first menstral cycle has been chosen you get anchored down the page to see the result?

You can see the implementation here if that helps.
https://www.theearlyyears.co.uk/pregnancy-due-date-calculator/

Again thanks in advance.

Thanks so much for this it has worked perfectly.

I look forward to using this for future projects too!