How can I re-render javascript onchange of a text field?

I am not a computer scientist, but a mechanical engineer by trade. Therefore, I apologize in advance if I do not use the correct words to describe things. I will try my best to be clear.

I'm working on a Rails site that displays the power output of a customer's solar power inverter. On the page where the power output is plotted (with javascript) I would like for the javascript (with embedded ruby) on that page to be re-rendered onchange of a text field (which has a date in it). As in when the customer wants to view their power output data for a different date, the javascript for this page will be re-rendered accordingly.

I was originally trying to use render :update and page.replace_html in a controller action that would be called onchange of the text field, but after further research found that this is not considered good practice? Also and more importantly, I couldn't make it work (I'm so ashamed. Thank you so much to those responders who tried to help me!).

I watched Railscast #136 and am trying to adapt that information to what I need.

The page is poweroutput.html.erb. All of my javascript is within script tags in the main html file. The html for the text field element on poweroutput.html.erb is as follows (It does not work):

<%= text_field_tag(
      'dt', nil,
      {  :id => 'date-field',
         :class => 'dateformat-d-dt-m-dt-Y',
         :onchange => remote_开发者_JAVA百科function(
             :url => {:controller => 'pages', :action => 'poweroutput'})
      })
%>

So I thought that the above would basically just refresh/re-render the page onchange of the text field, but nothing happens.

Please help as I am tearing my hair out. I think part of my problem must be that I don't understand what the underlying Ajax function that is being called by the remote_function method is doing. If you can shed some light on this OR suggest a completely different method of re-rendering javascript onchange of a text field, I'd be so grateful!

Two things that I think might be wrong here:

1) Wrap your partial with div, as AJAX calls results render to divs:

<script type="text/javascript">
   <div id="poweroutputscript_partial">
     <%= render 'javascripts/poweroutputscript.html.erb' %>
   </div>
</script>

2) In your action, specify full path to the partial:

page.replace_html "poweroutputscript_partial", :partial => 'javascripts/poweroutputscript'

First I would use firebug or similar to check that the request was being sent when the text field changes. Next I would check to see what the response is. If it's a 500 error, check the application logs for a stack trace.

My guess is that the response will be a 500 error, probably because your update_poweroutput function is trying to render a partial that doesn't exist, I think you need to specify

:partial => 'javascripts/poweroutputscript.html.erb'

unless, of course, you're rendering a different partial that does exist in the pages view folder. In this case, are you setting all the necessary variables in the controller?