# Observe\_field

**URL:** <https://www.ruby-forum.com/t/observe-field/105995>\
**Category:** Rails\
**Created:** [June 5, 2007, 1:45pm UTC](https://www.ruby-forum.com/t/observe-field/105995 "2007-06-05T13:45:32Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![madhan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/aca169/32.png) [@madhan](https://www.ruby-forum.com/u/madhan)\
**Post date:** [June 5, 2007, 1:45pm UTC](https://www.ruby-forum.com/t/observe-field/105995/1 "2007-06-05T13:45:32Z")

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hi all,  
i have used observe\_field in my rhtml to select a hospital from a  
dropdown.  
how can i get the hospitals id in some other method with in a class.  
if i use params(…) method it returns nil value.

guide me if anyone knows…