Bootstrap输入框组件的学习代码，供大家参考，具体内容如下
<Meta charset="utf-8">
<Meta http-equiv="X-UA-Compatible" content="IE-edge">
<Meta name="viewport" content="width=device-width,initial-scale=1">
Bootstrap 101 Template
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<div class="input-group">
<span class="input-group-addon">@
<input type="text" class="form-control" placeholder="Username">
<div class="input-group">
<input type="text" class="form-control" placeholder="Username">
<span class="input-group-addon">@