使用引导程序垂直居中div

Question

I'm using bootstrap 4, i want to center the div with id of table vertically in the center of the view screen , i try to use ```align-items-center on it's parent element but that does not work.

here is my HTML :

<div id="gameTable" class="d-flex h-100">
        <div class="container align-items-center text-center h-100">
            <table class="table text-center" id="table">
              <tbody>
                <tr>
                  <td class="align-middle">1</td>
                  <td class="align-middle">2</td>
                  <td class="align-middle">3</td>
                </tr>
                <tr>
                  <td class="align-middle">4</td>
                  <td class="align-middle">5</td>
                  <td class="align-middle">6</td>
                </tr>
                <tr>
                  <td class="align-middle">7</td>
                  <td class="align-middle">8</td>
                  <td class="align-middle">9</td>
                </tr>
              </tbody>
            </table>
            <button class="btn btn-danger" id="quit">Quit Game</button>
        </div>
    </div>

and here is my css :

html, body {
    height: 100%;
}

#table {
    height: 70%;
}

#gameTable {
    height: 100%;
    display: none;
}

can anyone tell me what is wrong with my codes.

Answer 1

align-items-center should be used with the flexbox container ( d-flex ). You can also somplify your code like below:

 #table { height:70%; } 

 <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css" rel="stylesheet"> <div id="gameTable" class="d-flex align-items-center vh-100"> <div class="container text-center" id="table"> <table class="table text-center h-100"> <tbody> <tr> <td class="align-middle">1</td> <td class="align-middle">2</td> <td class="align-middle">3</td> </tr> <tr> <td class="align-middle">4</td> <td class="align-middle">5</td> <td class="align-middle">6</td> </tr> <tr> <td class="align-middle">7</td> <td class="align-middle">8</td> <td class="align-middle">9</td> </tr> </tbody> </table> <button class="btn btn-danger" id="quit">Quit Game</button> </div> </div>