Input groups are another way to provide the user with additional information about the data you expect them to enter in a specific form element. Bootstrap provides classes to add sections either before or after an input element. These sections can contain either text or any of the 200 Glyphicons included in Bootstrap.
Note
Bootstrap comes prepackaged with 200 Glyphicon Halfling icons. Normally, the Glyphicon Halflings icons that are set are not free, but their creator made them available to Bootstrap free of charge. You can read more about them at http://getbootstrap.com/components/.
To create a text input element to indicate to the user that we require them to enter a phone number into the field, we'll use the following markup:
<div class="form-group">
@Html.LabelFor(model => model.Phone, new { @class = "control-label col-md-2" })
<div class="col-sm-4 input-group">
<span class="input-group-addon">
<span class="glyphicon glyphicon...