Dropdown onchange event?

rubyonrails-talk
1

Hi, I have a dropdown menu which shows the categories available. When a user selects one I want the browser to redirect to the selected category. I now have this code I found on stackoverflow;

<%form_for :cat_form, :url => {:action => :viewflokkur_selected} do

f>%>

    <%= f.select :cat, @cats_for_mt, {:include_blank => "Flokkar mælitækis"}, :onchange =>             'window.location.href = "viewflokkur/" + this.getAttribute("value")'%> <%end%>

However, "value" appears to be null everytime, so I get thrown to http://localhost:3000/categories/viewflokkur/null. Is there something I need to do for this to work, or should I be doing something else? I don't really understand how to use observer_fields either, but that seems to be something I should be looking into, is it not?

Best regards, Sindri

2

this.getAttribute("value") won't work on a select input, since the select doesn't have a "value" attribute. Rather, it has a list of options, and one or more of them are selected.

Try this.selectedIndex.value instead.

3

Tim Shaffer wrote:

this.getAttribute("value") won't work on a select input, since the select doesn't have a "value" attribute. Rather, it has a list of options, and one or more of them are selected.

Try this.selectedIndex.value instead.

Thanks for the suggestion, this.selectedIndex.value does not work though, now I get http://localhost:3000/categories/viewflokkur/undefined. Anywhere I can look this up? :slight_smile:

4

Please post the HTML that is output from the form.

5

Hi,

This is the output HTML.

<form action="/categories/viewflokkur_selected" method="post"><div style="margin:0;padding:0;display:inline"><input name="authenticity_token" type="hidden" value="B2u5ULNr7IJ/ta0+hiAMBjmjEtTtc/yMAQQvSxFn2d0=" /></div>             <select id="cat_form_cat" name="cat_form[cat]" onchange="window.location.href = &quot;viewflokkur/&quot; + this.selectedIndex.value"><option value="">Flokkar mælitækis</option> <option value="Almennt">Almennt</option> <option value="Hjartasjúkraþjálfun">Hjartasjúkraþjálfun</option> <option value="Lungnasjúkraþjálfun">Lungnasjúkraþjálfun</option> <option value="Taugasjúkraþjálfun">Taugasjúkraþjálfun</option> <option value="Öldrunarsjúkraþjálfun">Öldrunarsjúkraþjálfun</option></select>           <br><br>         </form>

BR, Sindri

6

Hi again,

I've also been trying to solve this using observe_field, and that 'almost' seems to work. Here's the code:

<%=select_tag "cat_selected", options_for_select(@cats_for_mt)%> <%=observe_field 'cat_selected',       :url => {:action => :viewflokkur},       :with => 'cat',       :method => :get %>

When I change the value, development.log shows this.

Processing CategoriesController#viewflokkur (for 127.0.0.1 at 2010-06-12 12:04:33) [GET]   Parameters: {"cat"=>"Taugasjúkraþjálfun", "authenticity_token"=>"B2u5ULNr7IJ/ta0+hiAMBjmjEtTtc/yMAQQvSxFn2d0="} Rendering template within layouts/main Rendering categories/viewflokkur Completed in 21ms (View: 18, DB: 0) | 200 OK [http://localhost/categories/viewflokkur?cat=Taugasjúkraþjálfun&authenticity_token=B2u5ULNr7IJ%2Fta0%2BhiAMBjmjEtTtc%2FyMAQQvSxFn2d0%3D]

So I should be redirected to 'viewflokkur', but nothing happens in my browser. Is there something else I need to do?

BR, Sindri

7

Finally got it working, used this solution;

<%= select_tag "cat_selected", options_for_select(['Flokkar mælitækis']+@cats_for_mt),   :onchange => 'window.location.href = "viewflokkur_from_select/" + this.selectedIndex'%>

That gave me params[:id] = index-selected, so I created this new method viewflokkur_from_select wich gets @cats_for_mt[params[:id].to_i-1] and then redirects to viewflokkur with that value as params[:cat]. Not very pretty, and a whole lot uglier than I expected, but works...

Thanks everyone for the suggestions!

8

Hi, Try this if you wish to have your code clean :