Make Iframe to fit 100% of container's remaining height

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I want to design a web page with a banner and an iframe. I hope the iframe can fill all the remaining page height and be resized automatically as the browser is resizing. Is it possible to get it done without writing JavaScript code, only with CSS?

I tried to set height:100% on iframe, the result is quite close but the iframe tried to fill the whole page height, including the 30px height of banner div element, so I got unnecessary vertical scrollbar. It's not perfect.

I tried CSS margin, padding attribute on DIV to occupy the whole remaining height of a web page successfully, but the trick didn't work on iframe.

 <body>
    <div style="width:100%; height:30px; background-color:#cccccc;">Banner</div>
    <iframe src="http: //www.google.com.tw" style="width:100%; height:100%;"></iframe>
</body>

iframe css html
27 Answers

Update in 2019

TL;DR: Today the best option is - flexbox. Everything supports it nicely and has for years. Go for that and don't look back. Here is a code sample for flexbox:

body, html {width: 100%; height: 100%; margin: 0; padding: 0}
.row-container {display: flex; width: 100%; height: 100%; flex-direction: column; background-color: blue; overflow: hidden;}
.first-row {background-color: lime; }
.second-row { flex-grow: 1; border: none; margin: 0; padding: 0; }
<div class="row-container">
  <div class="first-row">
    <p>Some text</p>
    <p>And some more text</p>
  </div>
  <iframe src="https://jsfiddle.net/about" class="second-row"></iframe>
</div>

The rest of this answer is left for learning & historical reasons.

The trick is to understand what the 100% is taken of. Reading CSS specs can help you there.

To make a long story short - there is such a thing as "containing block" - which is not necessary the parent element. Simply said, it is the first element up the hierarchy that has position:relative or position:absolute. Or the body element itself if there is nothing else. So, when you say "width: 100%", it checks the width of the "containing block" and sets the width of your element to the same size. If there was something else there, then you might get contents of a "containing block" that are larger than itself (thus "overflowing").

Height works the same way. With one exception. You can't get height to 100% of the browser window. The very top level element, against which 100% can be calculated, is the body (or html? not sure) element, and that stretches just enough to contain its contents. Specifying height:100% on it will have no effect, because it has no "parent element" against which to measure 100%. Window itself doesn't count. ;)

To make something stretch exactly 100% of the window, you have two choices:

  1. Use JavaScript
  2. Don't use DOCTYPE. This is not a good practice, but it puts the browsers in "quirks mode", in which you can do height="100%" on elements and it will stretch them to the window size. Do note, that the rest of your page will probably have to be changed too to accommodate for the DOCTYPE changes.

Update: I'm not sure if I wasn't wrong already when I posted this, but this certainly is outdated now. Today you can do this in your stylesheet: html, body { height: 100% } and it will actually stretch to the whole of your viewport. Even with a DOCTYPE. min-height: 100% could also be useful, depending on your situation.

And I wouldn't advise anyone to make a quirks-mode document anymore either, because it causes way more headaches than solves them. Every browser has a different quirks-mode, so getting your page to look consistently across browsers becomes two orders of magnitude more difficult. Use a DOCTYPE. Always. Preferably the HTML5 one - <!DOCTYPE html>. It's easy to remember and works like a charm in all browsers, even the 10 years old ones.

The only exception is when you have to support something like IE5 or something. If you're there, then you're on your own anyway. Those ancient browsers are nothing like the browsers today, and little advice that is given here will help you with them. On the bright side, if you're there, you probably just have to support ONE kind of browser, which gets rid of the compatibility problems.

Good luck!

Update 2: Hey, it's been a long time! 6 years later, new options are on the scene. I just had a discussion in the comments below, here are more tricks for you that work in today's browsers.

Option 1 - absolute positioning. Nice and clean for when you know the precise height of the first part.

body, html {width: 100%; height: 100%; margin: 0; padding: 0}
.first-row {position: absolute;top: 0; left: 0; right: 0; height: 100px; background-color: lime;}
.second-row {position: absolute; top: 100px; left: 0; right: 0; bottom: 0; background-color: red }
.second-row iframe {display: block; width: 100%; height: 100%; border: none;}
<div class="first-row">
  <p>Some text</p>
  <p>And some more text</p>
</div>
<div class="second-row">
  <iframe src="https://jsfiddle.net/about"></iframe>
</div>

Some notes - the second-row container is needed because bottom: 0 and right: 0 doesn't work on iframes for some reason. Something to do with in being a "replaced" element. But width: 100% and height: 100% works just fine. display: block is needed because it's an inline element by default and whitespace starts creating weird overflows otherwise.

Option 2 - tables. Works when you don't know the height of the first part. You can use either actual <table> tags or do it the fancy way with display: table. I'll go for the latter because it seems to be in fashion these days.

body, html {width: 100%; height: 100%; margin: 0; padding: 0}
.row-container {display: table; empty-cells: show; border-collapse: collapse; width: 100%; height: 100%;}
.first-row {display: table-row; overflow: auto; background-color: lime;}
.second-row {display: table-row; height: 100%; background-color: red; overflow: hidden }
.second-row iframe {width: 100%; height: 100%; border: none; margin: 0; padding: 0; display: block;}
<div class="row-container">
  <div class="first-row">
    <p>Some text</p>
    <p>And some more text</p>
  </div>
  <div class="second-row">
    <iframe src="https://jsfiddle.net/about"></iframe>
  </div>
</div>

Some notes - the overflow: auto makes sure that the row always includes all of its contents. Otherwise floating elements can sometimes overflow. The height: 100% on the second row makes sure it expands as much as it can squeezing the first row as small as it gets.

Recommended: Option 3 - flexbox - The cleanest one of them all.

body, html {width: 100%; height: 100%; margin: 0; padding: 0}
.row-container {display: flex; width: 100%; height: 100%; flex-direction: column; background-color: blue; overflow: hidden;}
.first-row {background-color: lime; }
.second-row { flex-grow: 1; border: none; margin: 0; padding: 0; }
<div class="row-container">
  <div class="first-row">
    <p>Some text</p>
    <p>And some more text</p>
  </div>
  <iframe src="https://jsfiddle.net/about" class="second-row"></iframe>
</div>

Some notes - the overflow: hidden is because the iframe still generates some sort of overflow even with display: block in this case. It isn't visible in the fullscreen view or the snippet editor, but the small preview window gets an extra scrollbar. No idea what that is, iframes are weird.

user_413600

We use a JavaScript to solve this problem; here is the source.

var buffer = 20; //scroll bar buffer
var iframe = document.getElementById('ifm');

function pageY(elem) {
    return elem.offsetParent ? (elem.offsetTop + pageY(elem.offsetParent)) : elem.offsetTop;
}

function resizeIframe() {
    var height = document.documentElement.clientHeight;
    height -= pageY(document.getElementById('ifm'))+ buffer ;
    height = (height < 0) ? 0 : height;
    document.getElementById('ifm').style.height = height + 'px';
}

// .onload doesn't work with IE8 and older.
if (iframe.attachEvent) {
    iframe.attachEvent("onload", resizeIframe);
} else {
    iframe.onload=resizeIframe;
}

window.onresize = resizeIframe;

Note: ifm is the iframe ID

pageY() was created by John Resig (the author of jQuery)

MichAdel_18438280

Another way to do that would be to use the position: fixed; on parent node.
If I am not mistaken, position: fixed; ties the element to viewport, thus, once you give this node width: 100%; and height: 100%; properties, it will span over entire screen. From this point on, you can put <iframe> tag inside it and span it over remaining space (both in width and in height) with simple width: 100%; height: 100%; CSS instruction.

Example code

    body {
        margin: 0px;
        padding: 0px;
    }

    /* iframe's parent node */
    div#root {
        position: fixed;
        width: 100%;
        height: 100%;
    }

    /* iframe itself */
    div#root > iframe {
        display: block;
        width: 100%;
        height: 100%;
        border: none;
    }
   <html>
        <head>
            <title>iframe Test</title>
            <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        </head>
        <body>
            <div id="root">
                <iframe src="http://stackoverflow.com/">
                    Your browser does not support inline frames.
                </iframe>
            </div>
        </body>
    </html>

user_2402020

You can do it with DOCTYPE, but you have to use table. Check this out:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<style>
*{margin:0;padding:0}
html, body {height:100%;width:100%;overflow:hidden}
table {height:100%;width:100%;table-layout:static;border-collapse:collapse}
iframe {height:100%;width:100%}

.header {border-bottom:1px solid #000}
.content {height:100%}
</style>
</head>
<body>
<table>
    <tr><td class="header"><div><h1>Header</h1></div></td></tr>
    <tr><td class="content">
        <iframe src="http://google.com/" frameborder="0"></iframe></td></tr>
</table>
</body>
</html>
user_457120

MichAdel code works for me but I made some minor modification to get it work properly.

function pageY(elem) {
    return elem.offsetParent ? (elem.offsetTop + pageY(elem.offsetParent)) : elem.offsetTop;
}
var buffer = 10; //scroll bar buffer
function resizeIframe() {
    var height = window.innerHeight || document.body.clientHeight || document.documentElement.clientHeight;
    height -= pageY(document.getElementById('ifm'))+ buffer ;
    height = (height < 0) ? 0 : height;
    document.getElementById('ifm').style.height = height + 'px';
}
window.onresize = resizeIframe;
window.onload = resizeIframe;
user_5530320

Another alternative using vh

<iframe src='/' style="display:block; border:none; height:100vh; width:100%;"></iframe>
user_4543750

It's right, you are showing an iframe with 100% height respect to its container: the body.

Try this:

<body>
  <div style="width:100%; height:30px; background-color:#cccccc;">Banner</div>
  <div style="width:100%; height:90%; background-color:transparent;">
    <iframe src="http: //www.google.com.tw" style="width:100%; height:100%;">
    </iframe> 
  </div>
</body>

Of course, change the height of the second div to the height you want.

ARemesal_365990

I think you have a conceptual problem here. To say "I tried set height:100% on iframe, the result is quite close but the iframe tried to fill the whole page", well, when has "100%" not been equal to "whole"?

You have asked the iframe to fill the entire height of its container (which is the body) but unfortunately it has a block level sibling in the <div> above which you've asked to be 30px big. So the parent container total is now being asked to size to 100% + 30px > 100%! Hence scrollbars.

What I think you mean is that you would like the iframe to consume what's left like frames and table cells can, i.e. height="*". IIRC this doesn't exist.

Unfortunately to the best of my knowledge there is no way to effectively mix/calculate/subtract absolute and relative units either, so I think you're reduced to two options:

  1. Absolutely position your div, which will take it out of the container so the iframe alone will consume it's containers height. This leaves you with all manner of other problems though, but perhaps for what you're doing opacity or alignment would be ok.

  2. Alternatively you need to specify a % height for the div and reduce the height of the iframe by that much. If the absolute height is really that important you'll need to apply that to a child element of the div instead.

annakata_130180

You can do this by measuring the body size on load/resize events and setting the height to the (full height - banner height).

Note that currently in IE8 Beta2 you can't do this onresize as that event is currently broken in IE8 Beta2.

user_61440

or you can go old-school and use a frameset perhaps:

<frameset rows="30,*">
  <frame src="banner.swf"/>
  <frame src="inner.html" />
</frameset>
Amir_Arad_118130
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