蓝色警示框:信息提示
<div class="alert alert-block alert-info"><b>Tip:</b> Use blue boxes (alert-info) for tips and notes.If it’s a note, you don’t have to include the word “Note”.</div>
黄色警示框:警告
<div class="alert alert-block alert-warning"><b>Example:</b> Yellow Boxes are generally used to include additional examples or mathematical formulas.</div>
绿色警示框:成功
<div class="alert alert-block alert-success">Use green box only when necessary like to display links to related content.</div>
红色警示框:高危
<div class="alert alert-block alert-danger">It is good to avoid red boxes but can be used to alert users to not delete some important part of code etc.</div>