네비게이션바

트롭다운 버튼

.dropdown > button생성 > .dropdown-menu > .dropdown-item

<div class="container">
    <h3>트랍다운 버튼</h3>
    <div class="dropdown">
      <button class="btn btn-danger dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown"
        aria-haspopup="true" aria-expanded="false">
        트롭 버튼
      </button>
      <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
        <a class="dropdown-item" href="#">첫번째 링크</a>
        <a class="dropdown-item" href="https://www.google.co.kr/">두번째 링크</a>
        <a class="dropdown-item" href="#">세번째 링크</a>
      </div>
    </div>
  </div>

네비게이션바

  <!--  navbar-expand-md 화면크기조정 md사이즈 이상일때 네버바 버튼 사라지고 나타남  -->
  <!-- navbar-light글자색 검정, navbar-dark 글자색 흰색, bg-light 백그라운드색상light말고 다른색상 넣음 or style사용해서 원하는색 가능 -->
  <nav class="navbar navbar-expand-md navbar-dark" style="background-color:brown;">
    <!-- navbar-brand : 제목 -->
    <a class="navbar-brand" href="#">제목</a>
    <!-- navbar버튼(자동숨김) : 특정 화면 사이즈보다 작을때 나타남 -->
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"
      aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <!-- navbar버튼이 나타나면 navbar-collapse 아래의 태그가 사라짐 -->
    <div class="collapse navbar-collapse" id="navbarSupportedContent">
      <ul class="navbar-nav mr-auto">
        <li class="nav-item active">
          <a class="nav-link" href="#">홈 <span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">링크</a>
        </li>
      </ul>
      <form class="form-inline my-2 my-lg-0">
        <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
        <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
      </form>
    </div>
  </nav>

특정 화면사이즈보다 작아질때