# How to add onchanget event to select field

**URL:** <https://www.ruby-forum.com/t/how-to-add-onchanget-event-to-select-field/164127>\
**Category:** Rails\
**Created:** [March 28, 2009, 8:54am UTC](https://www.ruby-forum.com/t/how-to-add-onchanget-event-to-select-field/164127 "2009-03-28T08:54:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ple\_mazako](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/5daacb/32.png) [@ple\_mazako](https://www.ruby-forum.com/u/ple_mazako)\
**Post date:** [March 28, 2009, 8:54am UTC](https://www.ruby-forum.com/t/how-to-add-onchanget-event-to-select-field/164127/1 "2009-03-28T08:54:53Z")

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Hello,  
I would like to add javascript ‘onChange’ event handling for a select  
field, such as

  
Modifiers  
\<%= form.select :s\_modify, ([ “Frequency”, “Genotype”,  
“Germline”, “Group”, “Haplotype”, , “Metagenomic”, “Pathovar”,  
“Plasmid-name”, “Plastid-name”, “Pop-variant” , “Rearranged”,  
“Segment”, “Subclone”, “Subgroup”, “Substrain”, “Subtype”, “Synonym”,  
“Transgenic”, “Type”, “Variety” ]) %\>  
Value  
\<%= form.text\_field :vaule\_sm%\>  

by if user select Metagenomic or 'Germline or ‘Rearranged’ or  
'Transgeni.

the vaule\_sm is “TRUE”

Anyone know how to make this work?