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March 19, 2012 11:40
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Backwards compatible window.postMessage(), by Josh Fraser, 15 January 2010 | http://onlineaspect.com/uploads/postmessage/postmessage.js
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/* | |
* a backwards compatable implementation of postMessage | |
* by Josh Fraser (joshfraser.com) | |
* released under the Apache 2.0 license. | |
* | |
* this code was adapted from Ben Alman's jQuery postMessage code found at: | |
* http://benalman.com/projects/jquery-postmessage-plugin/ | |
* | |
* other inspiration was taken from Luke Shepard's code for Facebook Connect: | |
* http://github.com/facebook/connect-js/blob/master/src/core/xd.js | |
* | |
* the goal of this project was to make a backwards compatable version of postMessage | |
* without having any dependency on jQuery or the FB Connect libraries | |
* | |
* my goal was to keep this as terse as possible since my own purpose was to use this | |
* as part of a distributed widget where filesize could be sensative. | |
* | |
*/ | |
// everything is wrapped in the XD function to reduce namespace collisions | |
var XD = function(){ | |
var interval_id, | |
last_hash, | |
cache_bust = 1, | |
attached_callback, | |
window = this; | |
return { | |
postMessage : function(message, target_url, target) { | |
if (!target_url) { | |
return; | |
} | |
target = target || parent; // default to parent | |
if (window['postMessage']) { | |
// the browser supports window.postMessage, so call it with a targetOrigin | |
// set appropriately, based on the target_url parameter. | |
target['postMessage'](message, target_url.replace( /([^:]+:\/\/[^\/]+).*/, '$1')); | |
} else if (target_url) { | |
// the browser does not support window.postMessage, so set the location | |
// of the target to target_url#message. A bit ugly, but it works! A cache | |
// bust parameter is added to ensure that repeat messages trigger the callback. | |
target.location = target_url.replace(/#.*$/, '') + '#' + (+new Date) + (cache_bust++) + '&' + message; | |
} | |
}, | |
receiveMessage : function(callback, source_origin) { | |
// browser supports window.postMessage | |
if (window['postMessage']) { | |
// bind the callback to the actual event associated with window.postMessage | |
if (callback) { | |
attached_callback = function(e) { | |
if ((typeof source_origin === 'string' && e.origin !== source_origin) | |
|| (Object.prototype.toString.call(source_origin) === "[object Function]" && source_origin(e.origin) === !1)) { | |
return !1; | |
} | |
callback(e); | |
}; | |
} | |
if (window['addEventListener']) { | |
window[callback ? 'addEventListener' : 'removeEventListener']('message', attached_callback, !1); | |
} else { | |
window[callback ? 'attachEvent' : 'detachEvent']('onmessage', attached_callback); | |
} | |
} else { | |
// a polling loop is started & callback is called whenever the location.hash changes | |
interval_id && clearInterval(interval_id); | |
interval_id = null; | |
if (callback) { | |
interval_id = setInterval(function(){ | |
var hash = document.location.hash, | |
re = /^#?\d+&/; | |
if (hash !== last_hash && re.test(hash)) { | |
last_hash = hash; | |
callback({data: hash.replace(re, '')}); | |
} | |
}, 100); | |
} | |
} | |
} | |
}; | |
}(); |
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