Form is submitted when I click on the button in form. How to avoid this?

Question

I use twitter-boostrap and I'd like to use these radio-buttons in my form. The problem is when I click on any of these buttons, the form is immediately submitted. How to avoid this? I just want to use default buttons like radio-buttons.

from:

<%= form_for @product do |f| %>
    <div class="control-group">
      <%= f.label :type, :class => 'control-label' %>

      <div class="controls">
        <div class="btn-group" data-toggle="buttons-radio">
          <button class="btn">Button_1</button>
          <button class="btn">Button_2</button>
        </div>
      </div>

    </div>

    <div class="form-actions">
      <%= f.submit nil, :class => 'btn btn-primary' %>
      <%= link_to 'Cancel', products_path, :class => 'btn' %>
    </div>
<% end %>

javascript:

// application.js
$('.tabs').button();

Answer 1

From the fine HTML5 specification:

A button element with no type attribute specified represents the same thing as a button element with its type attribute set to "submit".

And a <button type="submit"> submits the form rather than behaving like a simple <button type="button"> push-button.

The HTML4 spec says the same thing:

type = submit|button|reset [CI]
This attribute declares the type of the button. Possible values:

• submit: Creates a submit button. This is the default value.
• reset: Creates a reset button.
• button: Creates a push button.

So your <button> elements:

<button class="btn">Button_1</button> <button class="btn">Button_2</button> 

are the same as these (in compliant browsers):

<button type="submit" class="btn">Button_1</button> <button type="submit" class="btn">Button_2</button> 

and any time you hit one of those buttons you'll submit your form.

The solution is to use plain buttons:

<button type="button" class="btn">Button_1</button> <button type="button" class="btn">Button_2</button> 

Some versions of IE default to type="button" despite what the standard says. You should always specify the type attribute when using a <button> just to be sure that you will get the behavior you're expecting.