Some snippets to store facebook chat history.

export.js

window.conversation = (function() {

var conversation = [];

Array.prototype.forEach.call(
	document.querySelectorAll('#MessagingMessages .MessagingMessage'),
	function(block) {
		var sender = block.querySelector('.uiProfilePhoto').getAttribute('alt');
		var timestamp = block.querySelector('abbr.timestamp').getAttribute('data-utime');
		var messages = [];

		Array.prototype.forEach.call(
			block.querySelectorAll('.uiListItem .content'),
			function(message) {
				messages.push(message.innerHTML);
			}
		);

		conversation.push({
			'sender': sender,
			'timestamp': timestamp,
			'messages': messages
		});
	}
);

return conversation;

})();

load.js

(function() {

var scrollToTop, scrollToTopTimeout;

scrollToTop = function() {
	document.body.scrollTop = 0;
};

document.getElementById('MessagingScroller').addEventListener('DOMSubtreeModified', function(e) {
	clearTimeout(scrollToTopTimeout);
	scrollToTopTimeout = setTimeout(scrollToTop, 100);
});

scrollToTop();

})();

print.js

var output = window.open();
var pre = output.document.createElement('pre');
output.document.body.appendChild(pre);
pre.appendChild(output.document.createTextNode(JSON.stringify(conversation)));