h5p-php-library/js/h5p-resizer.js

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3.5 KiB
JavaScript
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// H5P iframe Resizer
(function () {
if (!window.postMessage || !window.addEventListener || window.h5pResizerInitialized) {
return; // Not supported
}
window.h5pResizerInitialized = true;
// Map actions to handlers
var actionHandlers = {};
/**
* Prepare iframe resize.
*
* @private
* @param {Object} iframe Element
* @param {Object} data Payload
* @param {Function} respond Send a response to the iframe
*/
actionHandlers.hello = function (iframe, data, respond) {
// Make iframe responsive
iframe.style.width = '100%';
// Tell iframe that it needs to resize when our window resizes
var resize = function (event) {
if (iframe.contentWindow) {
// Limit resize calls to avoid flickering
respond('resize');
}
else {
// Frame is gone, unregister.
window.removeEventListener('resize', resize);
}
};
window.addEventListener('resize', resize, false);
// Respond to let the iframe know we can resize it
respond('hello');
};
/**
* Prepare iframe resize.
*
* @private
* @param {Object} iframe Element
* @param {Object} data Payload
* @param {Function} respond Send a response to the iframe
*/
actionHandlers.prepareResize = function (iframe, data, respond) {
responseData = {};
// Create spaceholder and insert after iframe.
var spaceholder = document.createElement('div');
spaceholder.style.height = (iframe.clientHeight - 1) + 'px';
iframe.parentNode.insertBefore(spaceholder, iframe.nextSibling);
// Reset iframe height, in case content has shrinked.
iframe.style.height = '1px';
respond('resizePrepared');
};
/**
* Resize parent and iframe to desired height.
*
* @private
* @param {Object} iframe Element
* @param {Object} data Payload
* @param {Function} respond Send a response to the iframe
*/
actionHandlers.resize = function (iframe, data, respond) {
// Resize iframe so all content is visible.
iframe.style.height = data.height + 'px';
iframe.parentNode.removeChild(iframe.nextSibling);
};
/**
* Keyup event handler. Exits full screen on escape.
*
* @param {Event} event
*/
var escape = function (event) {
if (event.keyCode === 27) {
exitFullScreen();
}
};
// Listen for messages from iframes
window.addEventListener('message', function receiveMessage(event) {
if (event.data.context !== 'h5p') {
return; // Only handle h5p requests.
}
// Find out who sent the message
var iframe, iframes = document.getElementsByTagName('iframe');
for (var i = 0; i < iframes.length; i++) {
if (iframes[i].contentWindow === event.source) {
iframe = iframes[i];
break;
}
}
if (!iframe) {
return; // Cannot find sender
}
// Find action handler handler
if (actionHandlers[event.data.action]) {
actionHandlers[event.data.action](iframe, event.data, function respond(action, data) {
if (data === undefined) {
data = {};
}
data.action = action;
data.context = 'h5p';
event.source.postMessage(data, event.origin);
});
}
}, false);
// Let h5p iframes know we're ready!
var iframes = document.getElementsByTagName('iframe');
var ready = {
context: 'h5p',
action: 'ready'
};
for (var i = 0; i < iframes.length; i++) {
if (iframes[i].src.indexOf('h5p') !== -1) {
iframes[i].contentWindow.postMessage(ready, '*');
}
}
})();