CSS to centralise a HTML5 div at the bottom of the screen

问题

I have the following HTML5 document:

<canvas id="myCanvas">
</canvas>
<img id="logo" src="/images/logo.png" style="visibility:collapse" />
<div id="adControl" style="width: 728px; height: 90px; border: solid 1px red; visibility:visible;"
    data-win-control="MicrosoftNSJS.Advertising.AdControl"
    data-win-options="{applicationId: 'xyz', adUnitId: '123'}">
</div>

I'm trying to make the adcontrol appear in the centre at the bottom of the screen, beneath the canvas. Here's my CSS:

#adControl {   

    float:left; 

    margin: 0px auto;

}

#myCanvas {

    float:left;

}

I've tried various combinations of margin for the adcontrol, but don't seem to be able to centralise it.

回答1:

Do yo mean something like this?

.box {
    width:1024px;
    margin: 0px auto;
}
#adControl {   
    position:fixed;
    bottom:0;
    width: 728px; 
    height: 90px;
    border: solid 1px red; 
    visibility:visible;
}

回答2:

In WinJS app for windows 8, you can use -ms-grid and -ms-flexbox to achieve this.

html:

<div class="mypage fragment">
    <header aria-label="Header content" role="banner">
        <button class="win-backbutton" aria-label="Back" disabled type="button"></button>
        <h1 class="titlearea win-type-ellipsis">
            <span class="pagetitle">My Page</span>
        </h1>
    </header>    
    <section role="main">
        <canvas id="myCanvas">
        </canvas>
        <div class="ad-area-host">
            <div class="ad-area" style="width: 728px; height: 90px; border: solid 1px red; visibility:visible;"
               data-win-control="MicrosoftNSJS.Advertising.AdControl"
               data-win-options="{applicationId: 'xyz', adUnitId: '123'}">
            </div>
        </div>
    </section>
</div>

css:

// some of the css for fragment and section[role=main] already exists in default.css
.fragment 
{
    width: 100%;
    height: 100%;
    /* Define a grid with rows for a banner and a body */
    -ms-grid-columns: 1fr;
    -ms-grid-rows: 128px 1fr;
    display: -ms-grid;
}

.mypage.fragment section[role=main] 
{
    -ms-grid-row: 2;
    display: -ms-grid;
    -ms-grid-rows: 1fr auto;
    -ms-grid-columns: 1fr;
}

.ad-area-host
{
    -ms-grid-row: 2;
    height: 90px;
    display: -ms-flexbox;
    -ms-flex-direction: column;
    -ms-flex-align: center;
}

I have not tested this. give it a try. the idea is to use grid to align ad-area-host at bottom. then, use -ms-flexbox display in ad-area-host div to center the ad-area.

回答3:

#adControl {
    position: fixed;
    bottom: 0;
    left: 50%;
    transform: translate( -50%, 0);
    -ms-transform: translate( -50%, 0); 
    -webkit-transform: translate( -50%, 0);
}

Do you mean something like this?

回答4:

Or do you mean something like this ?

#adControl {   
position: relative;
width: 728px;
margin: 0px auto;
top: 200px;
margin-top: 100px;
height: 90px;
border: solid 1px red;
visibility:visible
}

回答5:

You should actually remove float: left from the below div to make it in center.

Try this:

 #adControl { 
      clear:left; 
      margin: 0px auto; 
 }

回答6:

hi have a look at this,

http://jsfiddle.net/SnjWs/1/

let me know if it helps

#adControl {
    width:728px;
    margin: 0px auto;
    height:90px;
    border: solid 1px red;
    visibility:visible;
}
#myCanvas {
    width:200px;
    border:1px solid black;
}

<canvas id="myCanvas"></canvas>
<img id="logo" src="/images/logo.png" style="visibility:collapse" />
<div id="adControl" data-win-control="MicrosoftNSJS.Advertising.AdControl" data-win-options="{applicationId: 'xyz', adUnitId: '123'}"></div>

回答7:

I haven't tried with a canvas but it shouldn't matter much. I've used this to bottom and center an ad that is 728x90

.wideAdTile {
    position: fixed;
    bottom: 0;
    left: 50%;
    margin-left: -364px; /*negative half the width of the ad*/
    width: 728px;
    height: 90px;
    z-index: 1;
}

and the html

<div class="wideAdTile" id="wideAd"
    data-win-control="MicrosoftNSJS.Advertising.AdControl"
    data-win-options="{ applicationId: 'd25517cb-12d4-4699-8bdc-52040c712cab', adUnitId: '10043000' }">
</div>

来源：https://stackoverflow.com/questions/16670025/css-to-centralise-a-html5-div-at-the-bottom-of-the-screen