namdx1987gmail.com / Math on facebook

// ==UserScript==
// @name        Math on facebook
// @namespace   http://scripts.namdx1987.org
// @author		namdx1987
// @description Display math on facebook
// @include     https://www.facebook.com/*
// @include		https://www.messenger.com/*
// @version     0.6
// @icon		https://s28.postimg.org/m7jtd71x9/fbmath128_01.png
// @icon64		https://s28.postimg.org/m7jtd71x9/fbmath128_01.png
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// @grant		GM_addStyle
// @grant		GM_getResourceText
// @grant       GM_log
// @connect		cdnjs.cloudflare.com
// @domain		cdnjs.cloudflare.com
// @noframes
// ==/UserScript==
//utilities

function el(html) {
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function addStyle(uri) {
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}

function gmIconSrc() {
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//script

function errSpan(msg) {
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function createUI() {
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`
<div style="position: fixed; top:0; z-index: 1000">
<div style="padding: 5px">
Textual content
</div>
<div style="padding: 5px">
<textarea id="mathpad" rows="30" cols="80"></textarea>
</div>
<div style="padding: 5px">
Preview
</div>
<div id="mathpreview" style="padding: 5px">
</div>
</div>
`);

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}

//createUI();

function showScriptInfo(info, engine) {
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			//engine(info);
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	icon.addEventListener('dblclick', function (evt) {
		//monkey.parentElement.removeChild(monkey);


	})
}

document.body.appendChild(el('<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.7.1/katex.min.css" crossorigin="anonymous"/>'));
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			break;

		idx = m.index;

		if (idx > lastIndex)
			span.appendChild(document.createTextNode(s.substring(lastIndex, idx)));

		var mathBlock = document.createElement("span");

		try {
			katex.render(m[2], mathBlock, {
				displayMode : (m[1] == "$$$") ? true : false,
				throwOnError : false
			});
		} catch (exc) {
			mathBlock.appendChild(errSpan(exc));
		}
		span.appendChild(mathBlock);
		//span.appendChild(document.createElement("span")).textContent=m[2];

		lastIndex = idx + m[0].length;
	}

	if (lastIndex < s.length)
		span.appendChild(document.createTextNode(s.substring(lastIndex)));

	return span;
}

function process(tnode) {
	if (!tnode.parentElement)
		return;

	tnode.replaceWith(createMathSpan(tnode.textContent));
}

function processSubTree(node) {
	for (var tn of queryTextNodes(node))
		//try{
		process(tn);
	//}
	//catch(exc)
	//{
	//	notie.alert(3, exc, 4);
	//}
}

var matchIds = ["u_json"];
var matchClasses = ["UFIComment", "_3b-9", "_5pcb", "_4tdt", "_o46", "mbm"];
//var showElem=false;

var streamWatcher = new MutationObserver(function (mutations, self) {
		for (var m of mutations)
			if (m.type == "childList")
				for (var el of m.addedNodes) {
					//console.log("original", el);

					//if(showElem)
					//	console.log("elem", el);

					if (el.nodeType != document.ELEMENT_NODE)
						continue;

					var found = false;

					if (el.hasAttribute("id"))
						for (var mtid of matchIds)
							if (el.getAttribute("id").startsWith(mtid)) {
								found = true;
								break;
							}

					if (!found)
						for (var mtcl of matchClasses)
							if (el.classList.contains(mtcl)) {
								found = true;
								break;
							}

					if (found) {
						processSubTree(el);
						//console.log(el);
					}
				}
	});

function beginWatch() {
	//for(var n of document.querySelectorAll("div[id^=feed_stream]>div[id^=more]>div[id^=u_ps]"))
	streamWatcher.observe(document.body, {
		childList : true,
		subtree : true
	});

	document.body.addEventListener('dblclick', function (evt) {
	//	//evt.stopPropagation();
		processSubTree(document.body);
	});
}