get value from a collection_select

Hello, how can i get the values of a form that has been filled out but was not sent to the database. i have a collection_select formfield and i need the selected item to fill an DIV with content specific to the selected item.

In Javascritp i´ve done it in this way:

  for (i = 0; i < document.formular.zeitung.length; ++i)     if (document.formular.zeitung.options[i].selected == true){       var textinhalt = document.formular.zeitung.options[i].value;   }

So in textinhalt the value is stored. How can i achieve this with ruby?

tia