CSS 缩放高度匹配宽度-可能与一个形式因子

For this, you will need to utilise JavaScript, or rely on the somewhat supported calc() CSS expression.

window.addEventListener("resize", function(e) {
var mapElement = document.getElementById("map");
mapElement.style.height = mapElement.offsetWidth * 1.72;
});

Or using CSS calc (see support here: http://caniuse.com/calc)

#map {
width: 100%;
height: calc(100vw * 1.72)
}

Let me describe the JS solution as a separate answer:

function handleResize()
{
var mapElement = document.getElementById("map");
mapElement.style.height = (mapElement.offsetWidth * 1.72) + "px";
}


<div id="map" onresize="handleResize()">...</div>

(or register the event listener dynamically).

mapElement.style.width * 1.72 will not work, since it requires that the width be set explicitly on the element, either using the width DOM attribute or in the inline style's width CSS property.

Here it is. Pure CSS. You do need one extra 'container' element.

The fiddle

(tinkerbin, actually): http://tinkerbin.com/rQ71nWDT (Tinkerbin is dead.)

The solution.

Note I'm using an 100% throughout the example. You can use whichever percentage you'd like.

Since height percentages are relative to the height of the parent element, we can't rely on it. We must rely on something else. Luckily padding is relative to the width - whether it's horizontal or vertical padding. In padding-xyz: 100%, 100% equals 100% of the box's width.

Unfortunately, padding is just that, padding. The content-box's height is 0. No problem!

Stick an absolutely positioned element, give it 100% width, 100% height and use it as your actual content box. The 100% height works because percentage heights on absolutely positioned elements are relative to the padding-box of the box their relatively positioned to.

HTML:

<div id="map_container">
<div id="map">
</div>
</div>

CSS:

#map_container {
position: relative;
width: 100%;
padding-bottom: 100%;
}


#map {
position: absolute;
width: 100%;
height: 100%;
}

I need to do "fluid" rectangles not squares.... so THANKS to JOPL .... didn't take but a minute....

#map_container {
position: relative;
width: 100%;
padding-bottom: 75%;
}




#map {
position:absolute;
width:100%;
height:100%;
}

You could try using vw for height. https://developer.mozilla.org/en/docs/Web/CSS/length

Something like

div#map {
width: 100%;
height: 60vw;
}

This would set the width of the div to 60% of the viewport width. You will probably need to use calc to adjust to take padding into account …

.video {
width: 100%;
position: relative;
padding-bottom: 56.25%; /* ratio 16/9 */
}


.video iframe {
border: none;
position: absolute;
width: 100%;
height: 100%;
}

16:9

padding-bottom = 9/16 * 100 = 56.25

Solution with Jquery

$(window).resize(function () {
var width = $("#map").width();
$("#map").height(width * 1.72);
});

Try viewports

You can use the width data and calculate the height accordingly

This example is for an 150x200px image

width: calc(100vw / 2 - 30px);
height: calc((100vw/2 - 30px) * 1.34);

#map {
width: 100%;
height: 100vw * 1.72
}

You can set its before and after to force a constant width-to-height ratio

HTML:

<div class="squared"></div>

CSS:

.squared {
background: #333;
width: 300px;
}
.squared::before {
content: '';
padding-top: 100%;
float: left;
}
.squared::after {
content: '';
display: block;
clear: both;
}

I've made similar thing with YouTube's IFRAME where the iframe is inside a grid that always changed based on portrait/landscape so this code worked for:

So the code for this question is:

// Layout resize
let height = window.innerHeight;
let width = window.document.getElementById('player').parentNode.clientWidth;
height = width / 1.77;

<div id="player"></div>


... etc ..


function onYouTubeIframeAPIReady() {
// Layout resize
let height = window.innerHeight;
let width = window.document.getElementById('player').parentNode.clientWidth;
height = width / 1.77;


player = new YT.Player('player', {
width: '100%',
height: height,
videoId: currentVideoId,
playerVars: {
'autoplay': 0,
'loop': 0,
'mute': 0,
'controls': 0,
'enablejsapi': 1,
'playsinline': 0,
'rel': 0,
'widget_referrer': 'http://my domain ...'
},
events: {
'onReady': onPlayerReady,
'onStateChange': onPlayerStateChange,
'onError': onError
}
});
}

You can use CSS like this to crop the image to a certain ratio and then using object-fit to center the image as you want.

CSS:

.ratio-crop {
aspect-ratio: 1.72 / 1; //using the example size in the question
object-fit: cover;
}

HTML:

<img src="/images.jpg" class="ratio-crop">