path: root/js/readability.js

var readabilityVersion = "0.3";

(function(){
	var objOverlay = document.createElement("div");
	var objinnerDiv = document.createElement("div");

	objOverlay.id = "readOverlay";
	objinnerDiv.id = "readInner";

	document.body.readability = {"contentScore": 0, originalHTML: document.body.innerHTML.toString()};
	
	// Apply user-selected styling:
	document.body.className = readStyle;
	objOverlay.className = readStyle;
	objinnerDiv.className = readMargin + " " + readSize;
	
	objinnerDiv.appendChild(grabArticle());		// Get the article and place it inside the inner Div
	objOverlay.appendChild(objinnerDiv);		// Insert the inner div into the overlay

	// For totally hosed HTML, add body node that can't be found because of bad HTML or something.
	if(document.body == null)
	{
		body = document.createElement("body");
		document.body = body;
	}

	document.body.innerHTML = "";
	
	// Inserts the new content :
	document.body.insertBefore(objOverlay, document.body.firstChild);
})()

function restoreDocument() {
	document.body.innerHTML = document.body.readability.originalHTML;
	for (var k=0;k < document.styleSheets.length; k++)
		if (document.styleSheets[k].href != null)
			document.styleSheets[k].disabled = (document.styleSheets[k].href.lastIndexOf("readability") != -1);

	// Enable all style tags in head:
	var styleTags = document.getElementsByTagName("style");
	for (var j=0;j < styleTags.length; j++)
		styleTags[j].disabled = false;

	return false;
}

function grabArticle() {
	var allParagraphs = document.getElementsByTagName("p");
	var topDivCount = 0;
	var topDiv = null;
	var topDivParas;
	
	var articleContent = document.createElement("DIV");
	var articleTitle = document.createElement("H1");
	var articleFooter = document.createElement("DIV");
	
	// Replace all doubled-up <BR> tags with <P> tags, and remove fonts.
	var pattern =  new RegExp ("<br/?>[ \r\n\s]*<br/?>", "g");
	document.body.innerHTML = document.body.innerHTML.replace(pattern, "</p><p>").replace(/<\/?font[^>]*>/g, '');
	
	// Grab the title from the <title> tag and inject it as the title.
	articleTitle.innerHTML = document.title;
	articleContent.appendChild(articleTitle);
	
	// Study all the paragraphs and find the chunk that has the best score.
	// A score is determined by things like: Number of <p>'s, commas, special classes, etc.
	for (var j=0; j	< allParagraphs.length; j++) {
		parentNode = allParagraphs[j].parentNode;

		// Initialize readability data
		if(typeof parentNode.readability == 'undefined')
		{
			parentNode.readability = {"contentScore": 0};			

			// Look for a special classname
			if(parentNode.className.match(/(comment|meta|footer|footnote)/))
				parentNode.readability.contentScore -= 50;
			else if(parentNode.className.match(/(hentry|entry[-]?(content|text|body)|article[-]?(content|text|body))/))
				parentNode.readability.contentScore += 25;

			// Look for a special ID
			if(parentNode.id.match(/(comment|meta|footer|footnote)/))
				parentNode.readability.contentScore -= 50;
			else if(parentNode.id.match(/(hentry|entry[-]?(content|text)|article[-]?(text|content))/))
				parentNode.readability.contentScore += 25;
		}

		// Add a point for the paragraph found
		if(getInnerText(allParagraphs[j]).length > 10)
			parentNode.readability.contentScore++;

		// Add points for any commas within this paragraph
		parentNode.readability.contentScore += getCharCount(allParagraphs[j]);
	}

	// Assignment from index for performance. See http://www.peachpit.com/articles/article.aspx?p=31567&seqNum=5 
	for(nodeIndex = 0; (node = document.getElementsByTagName('*')[nodeIndex]); nodeIndex++)
		if(typeof node.readability != 'undefined' && (topDiv == null || node.readability.contentScore > topDiv.readability.contentScore))
			topDiv = node;

	if(topDiv == null)
	{
	  topDiv = document.createElement('div');
	  topDiv.innerHTML = 'Sorry, readability was unable to parse this page for content. If you feel like it should have been able to, please <a href="http://code.google.com/p/arc90labs-readability/issues/entry">let us know by submitting an issue.</a>';
	}
	
	// REMOVES ALL STYLESHEETS ...
	for (var k=0;k < document.styleSheets.length; k++)
		if (document.styleSheets[k].href != null && document.styleSheets[k].href.lastIndexOf("readability") == -1)
			document.styleSheets[k].disabled = true;

	// Remove all style tags in head (not doing this on IE) :
	var styleTags = document.getElementsByTagName("style");
	for (var j=0;j < styleTags.length; j++)
		styleTags[j].disabled = true;
//		if (navigator.appName != "Microsoft Internet Explorer")
//			styleTags[j].textContent = "";


	cleanStyles(topDiv);					// Removes all style attributes
	topDiv = killDivs(topDiv);				// Goes in and removes DIV's that have more non <p> stuff than <p> stuff
	topDiv = killBreaks(topDiv);            // Removes any consecutive <br />'s into just one <br /> 

	// Cleans out junk from the topDiv just in case:
	topDiv = clean(topDiv, "form");
	topDiv = clean(topDiv, "object");
	topDiv = clean(topDiv, "table", 250);
	topDiv = clean(topDiv, "h1");
	topDiv = clean(topDiv, "h2");
	topDiv = clean(topDiv, "iframe");
	
	// Add the footer and contents:
	articleFooter.id = "readFooter";
	articleFooter.innerHTML = "\
		<a href='http://www.arc90.com'><img src='http://lab.arc90.com/experiments/readability/images/footer.png'></a>\
                <div class='footer-right' >\
                        <a href='#' onclick='return restoreDocument()'>Reload Page &raquo;</a>\
                        <span class='version'>Readability version " + readabilityVersion + "</span>\
		</div>\
	";
	
	articleContent.appendChild(topDiv);
	articleContent.appendChild(articleFooter);

	return articleContent;
}

// Get the inner text of a node - cross browser compatibly.
function getInnerText(e)
{
	if (navigator.appName == "Microsoft Internet Explorer")
		return e.innerText;
	else
		return e.textContent;
}

// Get character count
function getCharCount ( e,s ) {
    s = s || ",";
	return getInnerText(e).split(s).length;
}

function cleanStyles( e ) {
    e = e || document;
    var cur = e.firstChild;

	// If we had a bad node, there's not much we can do.
	if(!e)
		return;

	// Remove any root styles, if we're able.
	if(typeof e.removeAttribute == 'function')
		e.removeAttribute('style');

    // Go until there are no more child nodes
    while ( cur != null ) {
		if ( cur.nodeType == 1 ) {
			// Remove style attribute(s) :
			cur.removeAttribute("style");
			cleanStyles( cur );
		}
		cur = cur.nextSibling;
	}
}

function killDivs ( e ) {
	var divsList = e.getElementsByTagName( "div" );
	var curDivLength = divsList.length;
	
	// Gather counts for other typical elements embedded within.
	// Traverse backwards so we can remove nodes at the same time without effecting the traversal.
	for (var i=curDivLength-1; i >= 0; i--) {
		var p = divsList[i].getElementsByTagName("p").length;
		var img = divsList[i].getElementsByTagName("img").length;
		var li = divsList[i].getElementsByTagName("li").length;
		var a = divsList[i].getElementsByTagName("a").length;
		var embed = divsList[i].getElementsByTagName("embed").length;

	// If the number of commas is less than 10 (bad sign) ...
	if ( getCharCount(divsList[i]) < 10) {
			// And the number of non-paragraph elements is more than paragraphs 
			// or other ominous signs :
			if ( img > p || li > p || a > p || p == 0 || embed > 0) {
				divsList[i].parentNode.removeChild(divsList[i]);
			}
		}
	}
	return e;
}

function killBreaks ( e ) {
	e.innerHTML = e.innerHTML.replace(/(<br\s*\/?>(\s|&nbsp;?)*){1,}/g,'<br />');
	return e;
}

function clean(e, tags, minWords) {
	var targetList = e.getElementsByTagName( tags );
	minWords = minWords || 1000000;

	for (var y=0; y < targetList.length; y++) {
		// If the text content isn't laden with words, remove the child:
		if (getCharCount(targetList[y], " ") < minWords) {
			targetList[y].parentNode.removeChild(targetList[y]);
		}
	}
	return e;
}