设置选择选项的默认值

Question

I have a drop down select option like below

<select id="find_best" name="finding_best">
    <option value="10">One</option>
    <option value="20">Two</option>
    <option value="30">Three</option>
</select>

This is inside a form and when the form is submitted and if there are validation errors, selected option disappear. Say if I selected Three and then submit and if any validation error occur the page is reloaded and the option is not selected any more. Use has to select it again.

But I want to keep the selected option even after reloading the page after submiting the form. I tried this

 <% if defined?(params[:finding_best]) %>
        $("#find_best").val(<%= params[:finding_best] %>);
 <% end %> 

But this is not working. Let me how can I do this.

Answer 1

What you need to do, is add the selected attribute to the correct <option> element, so that the browser knows what was selected. Your final HTML should look something like this.

<select id="find_best" name="finding_best">
    <option value="10">One</option>
    <option value="20">Two</option>
    <option value="30" selected>Three</option>
</select>

Answer 2

In rails you have to use rails helper functions. If you are using form_for then write it with form object f.select

If you are using simple form tag then try this:

<%= select_tag :find_best, raw(options_for_select([['One', 10],['Two', 20],['Three', 30]], params[:find_best])) %>