# Autocalculate field in a form

**URL:** <https://www.ruby-forum.com/t/autocalculate-field-in-a-form/186207>\
**Category:** Ruby\
**Created:** [April 2, 2010, 4:49am UTC](https://www.ruby-forum.com/t/autocalculate-field-in-a-form/186207 "2010-04-02T04:49:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![nmathes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/439d5e/32.png) [@nmathes](https://www.ruby-forum.com/u/nmathes)\
**Post date:** [April 2, 2010, 4:49am UTC](https://www.ruby-forum.com/t/autocalculate-field-in-a-form/186207/1 "2010-04-02T04:49:28Z")

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Hi,

I have a form with the following fields

status - x,y,z  
rating-1,2,3

When customer selects the status and rating,the next filled  
automatically displays the correct likelihood according to the first two  
filed selections as follows.  
if status == x and rating == 1 then

liklihood- j.

Please help me to do this. Many thanks.

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<div class="post-metadata">

**Author:** ![nmathes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/439d5e/32.png) [@nmathes](https://www.ruby-forum.com/u/nmathes)\
**Post date:** [April 2, 2010, 9:43am UTC](https://www.ruby-forum.com/t/autocalculate-field-in-a-form/186207/2 "2010-04-02T09:43:26Z")

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You need Javascript for this.

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<div class="post-metadata">

**Author:** ![nmathes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/439d5e/32.png) [@nmathes](https://www.ruby-forum.com/u/nmathes)\
**Post date:** [April 4, 2010, 5:01am UTC](https://www.ruby-forum.com/t/autocalculate-field-in-a-form/186207/3 "2010-04-04T05:01:07Z")

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Brian C. wrote:

> You need Javascript for this.

Yes, because I’m new to Ruby can you please explain this for me. Thanks.

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<div class="post-metadata">

**Author:** ![nmathes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/439d5e/32.png) [@nmathes](https://www.ruby-forum.com/u/nmathes)\
**Post date:** [April 4, 2010, 9:48am UTC](https://www.ruby-forum.com/t/autocalculate-field-in-a-form/186207/4 "2010-04-04T09:48:32Z")

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Nipuna W. wrote:

> Brian C. wrote:
> 
> > You need Javascript for this.
> 
> Yes, because I’m new to Ruby can you please explain this for me. Thanks.

Questions about Javascript should be asked on a Javascript mailing list.

If you are using a web framework like Rails, then you need to  
incorporate your Javascript into the HTML pages you generate from your  
templates. So if you can’t see how to include the Javascript you’ve  
written into your pages, you could ask on a mailing list relevant to the  
framework you’re using (e.g. Rails, which has its own mailing lists)