[css] Set a button group's width to 100% and make buttons equal width?

I'm using Bootstrap, and I'd like to set an entire btn-group to have a width of 100% of its parent element. I'd also like the inner buttons to take equal widths. As it is, I can't achieve either.

I've made a JSFiddle here: http://jsfiddle.net/BcQZR/12/

Here is the HTML:

<div class="span8 background">
<div class="btn-group btn-block" id="colours">
<span class="btn"><input type='checkbox' name='size' value='red'/>red</span>
<span class="btn"><input type='checkbox' name='size' value='orange'/>orange</span>
<span class="btn"><input type='checkbox' name='size' value='yellow'/>yellow</span>
</div> <!-- /btn-group -->
</div>

And here is my current CSS, which doesn't work:

#colours { 
  width: 100%;
}

I don't like the solution of settings widths on .btn because it assumes there'll always be the same number of items in the .btn-group. This is a faulty assumption and leads to bloated, presentation-specific CSS.

A better solution is to change how .btn-group with .btn-block and child .btn(s) are display. I believe this is what you're looking for:

.btn-group.btn-block {
    display: table;
}
.btn-group.btn-block > .btn {
    display: table-cell;
}

Here's a fiddle: http://jsfiddle.net/DEwX8/123/

If you'd prefer to have equal-width buttons (within reason) and can support only browsers that support flexbox, try this instead:

.btn-group.btn-block {
    display: flex;
}
.btn-group.btn-block > .btn {
    flex: 1;
}

Here's a fiddle: http://jsfiddle.net/DEwX8/124/

Bootstrap 4 Solution

<div class="btn-group w-100">
    <button type="button" class="btn">One</button>
    <button type="button" class="btn">Two</button>
    <button type="button" class="btn">Three</button>
</div>

You basically tell the btn-group container to have width 100% by adding w-100 class to it. The buttons inside will fill in the whole space automatically.

Angular - equal width button group

Assuming you have an array of 'things' in your scope...

• Make sure the parent div has a width of 100%.
• Use ng-repeat to create the buttons within the button group.
• Use ng-style to calculate the width for each button.

<div class="btn-group"
     style="width: 100%;">
    <button ng-repeat="thing in things"
            class="btn btn-default"
            ng-style="{width: (100/things.length)+'%'}">
        {{thing}}
    </button>
</div>

For bootstrap 4 just add this class:

w-100

Bootstrap 4 removed .btn-group-justified. As a replacement you can use <div class="btn-group d-flex" role="group"></div> as a wrapper around elements with .w-100.

Try this:

<div class="btn-group d-flex" role="group>
  <button type="button" class="btn btn-primary w-100">Submit</button>
  <button type="button" class="btn btn-primary w-100">Cancel</button>
</div>

Bootstrap has the .btn-group-justified css class.

How it's structured is based on the type of tags you use.

With <a> tags

<div class="btn-group btn-group-justified" role="group" aria-label="...">
   ...
</div>

With <button> tags

<div class="btn-group btn-group-justified" role="group" aria-label="...">
  <div class="btn-group" role="group">
    <button type="button" class="btn btn-default">Left</button>
  </div>
  <div class="btn-group" role="group">
    <button type="button" class="btn btn-default">Middle</button>
  </div>
  <div class="btn-group" role="group">
    <button type="button" class="btn btn-default">Right</button>
  </div>
</div>

Bootstrap 4

            <ul class="nav nav-pills nav-fill">
                <li class="nav-item">
                    <a class="nav-link active" href="#">Active</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="#">Longer nav link</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="#">Link</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link disabled" href="#">Disabled</a>
                </li>
            </ul>

There's no need for extra css the .btn-group-justified class does this.

You have to add this to the parent element and then wrap each btn element in a div with .btn-group like this

    <div class="form-group">

            <div class="btn-group btn-group-justified">
                <div class="btn-group">
                    <button type="submit" id="like" class="btn btn-lg btn-success ">Like</button>
                </div>
                <div class="btn-group">
                    <button type="submit" id="nope" class="btn btn-lg btn-danger ">Nope</button>
                </div>
            </div>

        </div>