Height equal to dynamic width (CSS fluid layout) [duplicate]

Answer 1

Extremely simple method jsfiddle

HTML

<div id="container">
    <div id="element">
        some text
    </div>
</div>

CSS

#container {
    width: 50%; /* desired width */
}

#element {
    height: 0;
    padding-bottom: 100%;
}

Answer 2

There is a way using CSS!

If you set your width depending on the parent container you can set the height to 0 and set padding-bottom to the percentage which will be calculated depending on the current width:

.some_element {
    position: relative;
    width: 20%;
    height: 0;
    padding-bottom: 20%;
}

This works well in all major browsers.

JSFiddle: https://jsfiddle.net/ayb9nzj3/

Answer 3

Simple and neet : use vw units for a responsive height/width according to the viewport width.

vw : 1/100th of the width of the viewport. (Source MDN)

DEMO

HTML:

<div></div>

CSS for a 1:1 aspect ratio:

div{
    width:80vw;
    height:80vw; /* same as width */
}

---

Table to calculate height according to the desired aspect ratio and width of element.

   aspect ratio  |  multiply width by
    -----------------------------------
         1:1      |         1
         1:3      |         3
         4:3      |        0.75
        16:9      |       0.5625

---

This technique allows you to :

• insert any content inside the element without using position:absolute;
• no unecessary HTML markup (only one element)
• adapt the elements aspect ratio according to the height of the viewport using vh units
• you can make a responsive square or other aspect ratio that alway fits in viewport according to the height and width of the viewport (see this answer : Responsive square according to width and height of viewport or this demo)

These units are supported by IE9+ see canIuse for more info