Iframe-resizer

Size cross domain iFrames to content with support for window/content resizing, and multiple iFrames.

This project is maintained by davidjbradshaw

iFrame Resizer

This library enables the automatic resizing of the height and width of both same and cross domain iFrames to fit their contained content. It provides a range of features to address the most common issues with using iFrames, these include:

Getting started

The package contains two minified JavaScript files in the js folder. The first (iframeResizer.min.js) is for the page hosting the iFrames. It can be called with native JavaScript;

var iframes = iFrameResize( [{options}], [css selector] || [iframe] );

or via jQuery. (See notes below for using native version with IE8).

$('iframe').iFrameResize( [{options}] );

The second file (iframeResizer.contentWindow.min.js) is a native JavaScript file that needs placing in the page contained within your iFrame. This file is designed to be a guest on someone else's system, so has no dependencies and won't do anything until it's activated by a message from the containing page.

Typical setup

The normal configuration is to have the iFrame resize when the browser window changes size or the content of the iFrame changes. To set this up you need to configure one of the dimensions of the iFrame to a percentage and tell the library to only update the other dimension. Normally you would set the width to 100% and have the height scale to fit the content.

<style>iframe{width:100%}</style>
<iframe src="http://anotherdomain.com/iframe.html" scrolling="no"></iframe>
<script>iFrameResize({log:true})</script>

Note that scrolling is set to 'no' in the iFrame tag, as older versions of IE don't allow this to be turned off in code and can just slightly add a bit of extra space to the bottom of the content that it doesn't report when it returns the height. If you have problems, check the troubleshooting section below.

Example

To see this working take a look at this example and watch the console.

Options

log

default: false
type:    boolean

Setting the log option to true will make the scripts in both the host page and the iFrame output everything they do to the JavaScript console so you can see the communication between the two scripts.

autoResize

default: true
type:    boolean

When enabled changes to the Window size or the DOM will cause the iFrame to resize to the new content size. Disable if using size method with custom dimensions.

Note: When set to false the iFrame will still inititally size to the contained content, only additional resizing events are disabled.

bodyBackground

default: null
type:    string

Override the body background style in the iFrame.

bodyMargin

default: null
type:    string || number

Override the default body margin style in the iFrame. A string can be any valid value for the CSS margin attribute, for example '8px 3em'. A number value is converted into px.

checkOrigin

default: true
type:    boolean || array

When set to true, only allow incoming messages from the domain listed in the src property of the iFrame tag. If your iFrame navigates between different domains, ports or protocols; then you will need to provide an array of URLs or disable this option.

inPageLinks

default: false
type:    boolean

When enabled in page linking inside the iFrame and from the iFrame to the parent page will be enabled.

interval

default: 32  (in ms)
type:    number

In browsers that don't support mutationObserver, such as IE10, the library falls back to using setInterval, to check for changes to the page size. The default value is equal to two frame refreshes at 60Hz, setting this to a higher value will make screen redraws noticeable to the user.

Setting this property to a negative number will force the interval check to run instead of mutationObserver.

Set to zero to disable.

heightCalculationMethod

default: 'bodyOffset'
values:  'bodyOffset' | 'bodyScroll' | 'documentElementOffset' | 'documentElementScroll' |
         'max' | 'min' | 'grow' | 'lowestElement' | 'taggedElement'

By default the height of the iFrame is calculated by converting the margin of the body to px and then adding the top and bottom figures to the offsetHeight of the body tag.

In cases where CSS styles causes the content to flow outside the body you may need to change this setting to one of the following options. Each can give different values depending on how CSS is used in the page and each has varying side-effects. You will need to experiment to see which is best for any particular circumstance.

Notes:

If the default option doesn't work then the best solutions is to either to use taggedElement, or to use lowestElement in modern browsers and max in IE10 downwards.

var isOldIE = (navigator.userAgent.indexOf("MSIE") !== -1); // Detect IE10 and below

iFrameResize( {
    heightCalculationMethod: isOldIE ? 'max' : 'lowestElement'
});

The lowestElement option is the most reliable way of determining the page height. However, it does have a performance impact in older versions of IE. In one screen refresh (16ms) Chrome can calculate the position of around 10,000 html nodes, whereas IE 8 can calculate approximately 50. The taggedElement option provides much greater performance by limiting the number of elements that need their position checked.

* The bodyScroll, documentElementScroll, max and min options can cause screen flicker and will prevent the interval trigger downsizing the iFrame when the content shrinks. This is mainly an issue in IE 10 and below, where the mutationObserver event is not supported. To overcome this you need to manually trigger a page resize by calling the parentIFrame.size() method when you remove content from the page.

maxHeight / maxWidth

default: infinity
type:    integer

Set maximum height/width of iFrame.

minHeight / minWidth

default: 0
type:    integer

Set minimum height/width of iFrame.

resizeFrom

default: 'parent'
values: 'parent', 'child'

Listen for resize events from the parent page, or the iFrame. Select the 'child' value if the iFrame can be resized independently of the browser window. Selecting this value can cause issues with some height calculation methods on mobile devices.

scrolling

default: false
type:    boolean

Enable scroll bars in iFrame.

sizeHeight

default: true
type:    boolean

Resize iFrame to content height.

sizeWidth

default: false
type:    boolean

Resize iFrame to content width.

tolerance

default: 0
type:    integer

Set the number of pixels the iFrame content size has to change by, before triggering a resize of the iFrame.

widthCalculationMethod

default: 'scroll'
values:  'bodyOffset' | 'bodyScroll' | 'documentElementOffset' | 'documentElementScroll' |
         'max' | 'min' | 'scroll' | 'rightMostElement' | 'taggedElement'

By default the width of the page is worked out by taking the greater of the documentElement and body scrollWidth values.

Some CSS technics may require you to change this setting to one of the following options. Each can give different values depending on how CSS is used in the page and each has varying side-effects. You will need to experiment to see which is best for any particular circumstance.

The rightMostElement option is the most reliable way of determining the page width. However, it does have a performance impact in older versions of IE. In one screen refresh (16ms) Chrome can calculate the position of around 10,000 html nodes, whereas IE 8 can calculate approximately 50. The taggedElement option provides much greater performance by limiting the number of elements that need their position checked.

* The bodyScroll, documentElementScroll, max and min options can cause screen flicker and will prevent the interval trigger downsizing the iFrame when the content shrinks. This is mainly an issue in IE 10 and below, where the mutationObserver event is not supported. To overcome this you need to manually trigger a page resize by calling the parentIFrame.size() method when you remove content from the page.

Callback Methods

closedCallback

type: function (iframeID)

Called when iFrame is closed via parentIFrame.close() or iframe.iframeResizer.close() methods. See below for details.

initCallback

type: function (iframe)

Initial setup callback function.

messageCallback

type: function ({iframe,message})

Receive message posted from iFrame with the parentIFrame.sendMessage() method.

resizedCallback

type: function ({iframe,height,width,type})

Function called after iFrame resized. Passes in messageData object containing the iFrame, height, width and the type of event that triggered the iFrame to resize.

scrollCallback

type: function ({x,y})

Called before the page is repositioned after a request from the iFrame, due to either an in page link, or a direct request from either parentIFrame.scrollTo() or parentIFrame.scrollToOffset(). If this callback function returns false, it will stop the library from repositioning the page, so that you can implement your own animated page scrolling instead.

IFrame Page Options

The following options can be set from within the iFrame page by creating a window.iFrameResizer object before the JavaScript file is loaded into the page.

<script>
    window.iFrameResizer = {
        targetOrigin: 'http://mydomain.com'
    }
</script>
<script src="js/iframeresizer.contentwindow.js"></script>

targetOrigin

default: '*'
type: string

This option allows you to restrict the domain of the parent page, to prevent other sites mimicing your parent page.

messageCallback

type: function (message)

Receive message posted from the parent page with the iframe.iFrameResizer.sendMessage() method (See below for details).

readyCallback

type: function()

This function is called once iFrame-Resizer has been initialized after receiving a call from the parent page. If you need to call any of the parentIFrame methods (See below) during page load, then they should be called from this callback.

heightCalculationMethod / widthCalculationMethod

default: null
type: string

These options can be used to override the option set in the parent page (See above for details on available values). This can be useful when moving between pages in the iFrame that require different values for these options.

IFrame Page Methods

These methods are available in the iFrame via the window.parentIFrame object. These method should be contained by a test for the window.parentIFrame object, in case the page is not loaded inside an iFrame. For example:

if ('parentIFrame' in window) {
    parentIFrame.close();
}

autoResize([bool])

Turn autoResizing of the iFrame on and off. Returns bool of current state.

close()

Remove the iFrame from the parent page.

getId()

Returns the ID of the iFrame that the page is contained in.

getPageInfo(callback || false)

Ask the containing page for its positioning coordinates. You need to provide a callback which receives an object with the following properties:

Your callback function will be recalled when the parent page is scrolled or resized.

Pass false to disable the callback.

scrollTo(x,y)

Scroll the parent page to the coordinates x and y.

scrollToOffset(x,y)

Scroll the parent page to the coordinates x and y relative to the position of the iFrame.

sendMessage(message,[targetOrigin])

Send data to the containing page, message can be any data type that can be serialized into JSON. The targetOrigin option is used to restrict where the message is sent to; to stop an attacker mimicking your parent page. See the MDN documentation on postMessage for more details.

setHeightCalculationMethod(heightCalculationMethod)

Change the method use to workout the height of the iFrame.

size ([customHeight],[ customWidth])

Manually force iFrame to resize. This method optionally accepts two arguments: customHeight & customWidth. To use them you need first to disable the autoResize option to prevent auto resizing and enable the sizeWidth option if you wish to set the width.

iFrameResize({
    autoResize: false,
    sizeWidth: true
});

Then you can call the size method with dimensions:

if ('parentIFrame' in window) {
    parentIFrame.size(100); // Set height to 100px
}

IFrame Object Methods

Once the iFrame has been initialized, an iFrameResizer object is bound to it. This has the following methods available.

close()

Remove the iFrame from the page.

moveToAnchor(anchor)

Move to anchor in iFrame.

resize()

Tell the iFrame to resize itself.

sendMessage(message,[targetOrigin])

Send data to the containing page, message can be any data type that can be serialized into JSON. The targetOrigin option is used to restrict where the message is sent to, in case your iFrame navigates away to another domain.

Troubleshooting

The first steps to investigate a problem is to make sure you are using the latest version and then enable the log option, which outputs everything that happens to the JavaScript Console. This will enable you to see what both the iFrame and host page are up to and also see any JavaScript error messages.

Solutions for the most common problems are outlined in this section. If you need futher help, then please ask questions on StackOverflow with the iframe-resizer tag.

Bug reports and pull requests are welcome on the issue tracker. Please read the contributing guidelines before openning a ticket, as this will ensure a faster resolution.

IFrame not sizing correctly

If a larger element of content is removed from the normal document flow, through the use of absolute positioning, it can prevent the browser working out the correct size of the page. In such cases you can change the heightCalculationMethod to uses one of the other sizing methods.

IFrame not downsizing

The most likely cause of this problem is having set the height of an element to be 100% of the page somewhere in your CSS. This is normally on the html or body elements, but it could be on any element in the page. This can sometimes be got around by using the taggedElement height calculation method and added a data-iframe-height attribute to the element that you want to define the bottom position of the page. You may find it useful to use position: relative on this element to define a bottom margin or allow space for a floating footer.

Not having a valid HTML document type in the iFrame can also sometimes prevent downsizing. At it's most simplest this can be the following.

<!DOCTYPE html>

IFrame not resizing

The most common cause of this is not placing the iframeResizer.contentWindow.min.js script inside the iFramed page. If the other page is on a domain outside your control and you can not add JavaScript to that page, then now is the time to give up all hope of ever getting the iFrame to size to the content. As it is impossible to work out the size of the contained page, without using JavaScript on both the parent and child pages.

IFrame not detecting CSS :hover events

If your page resizes via CSS :hover events, these won't be detected by default. It is however possible to create mouseover and mouseout event listeners on the elements that are resized via CSS and have these events call the parentIFrame.size() method. With jQuery this can be done as follows

function resize(){
    if ('parentIFrame' in window) {
        // Fix race condition in FireFox with setTimeout
        setTimeout(parentIFrame.size.bind(parentIFrame),0);
    }
}

$(*Element with hover style*).hover(resize);

IFrame not detecting textarea resizes

Both FireFox and the WebKit based browsers allow the user to resize textarea input boxes. Unfortunately the WebKit browsers don't trigger the mutation event when this happens. This can be worked around to some extent with the following code.

function store(){
    this.x = this.offsetWidth;
    this.y = this.offsetHeight;
}

$('textarea').each(store).on('mouseover mouseout',function(){
    if (this.offsetWidth !== this.x || this.offsetHeight !== this.y){
        store.call(this);
        if ('parentIFrame' in window){
            parentIFrame.size();
        }
    }
});

IFrame flickers

Some of the alternate height calculation methods, such as max can cause the iFrame to flicker. This is due to the fact that to check for downsizing, the iFrame first has to be downsized before the new height can be worked out. This effect can be reduced by setting a minSize value, so that the iFrame is not reset to zero height before regrowing.

In modern browsers, if the default height calculation method does not work, then it is normally best to use lowestElement, which is flicker free, and then provide a fallback to max in IE10 downwards.

var isOldIE = (navigator.userAgent.indexOf("MSIE") !== -1); // Detect IE10 and below

iFrameResize({
    heightCalculationMethod: isOldIE ? 'max' : 'lowestElement',
    minSize:100
});

Please see the notes section under heightCalculationMethod to understand the limitations of the different options.

ParentIFrame not found errors

The parentIFrame object is created once the iFrame has been initially resized. If you wish to use it during page load you will need call it from the readyCallback.

<script>
    window.iFrameResizer = {
        readyCallback: function(){
            var myId = window.parentIFrame.getId();
            console.log('The ID of the iFrame in the parent page is: '+myId);
        }
    }
</script>
<script src="js/iframeresizer.contentwindow.js"></script>

PDF and OpenDocument files

It is not possible to add the required JavaScript to PDF and ODF files. However, you can get around this limitation by using ViewerJS to render these files inside a HTML page, that also contains the iFrame JavaScript file (iframeResizer.contentWindow.min.js).

Unexpected message received error

By default the origin of incoming messages is checked against the src attribute of the iFrame. If they don't match an error is thrown. This behaviour can be disabled by setting the checkOrigin option to false.

Browser compatibility

jQuery version

Basic support works with all browsers which support window.postMessage (IE8+). Some advanced features require the native version polyfil to work in IE8.

Native version

Additionally requires support for Array.prototype.forEach and Function.prototype.bind (IE9+), plus document.querySelectorAll (IE8 Standards Mode). For IE8 force Standards Mode and include the IE8 PolyFils on the host page.

<meta http-equiv="X-UA-Compatible" content="IE=edge">
<!--[if lte IE 8]>
    <script type="text/javascript" src="js/ie8.polyfils.min.js"></script>
<![endif]-->

Upgrading to version 3

The requirements for IE8 support in version 3 have changed from version 2. If you still require IE8 support than you will need to ensure you include the new ie8.polyfil.js file, as outlined above.

The parentIFrame methods object in the iFrame is now always available and the enablePublicMethods option has been removed. The enableInPageLinks option has been rename to inPageLinks.

Version History

License

Copyright © 2013-15 David J. Bradshaw. Licensed under the MIT License.

NPM NPM