E044 (Missing children within `.input group`)

E044

.input-group must have a .form-control and either .input-group-addon or .input-group-btn.

.input-groups are meant to contain both a .form-control and at least one addon such as .input-group-addon or .input-group-btn. Omitting the addon can cause the .form-control to lose styling. Omitting the control doesn't make sense and causes some styles to be lost. Ensure you have all the required element with the correct classes within an .input-group.

Wrong:

<div class="input-group">
  <input type="text" class="form-control" placeholder="Username" aria-describedby="basic-addon1">
</div>

<div class="input-group">
  <span class="input-group-addon" id="basic-addon1">@</span>
</div>

Right:

<div class="input-group">
  <span class="input-group-addon" id="basic-addon1">@</span>
  <input type="text" class="form-control" placeholder="Username" aria-describedby="basic-addon1">          
</div>

<div class="input-group">
  <input type="text" class="form-control" placeholder="Search for...">
  <span class="input-group-btn">
    <button class="btn btn-default" type="button">Go!</button>
  </span>
</div>