diff --git a/README.md b/README.md
index 3f9f97b..2b6eae5 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,16 @@
 Renders UML diagram as defined in a text file. For full syntax, see:
 http://plantuml.sourceforge.net/index.html
 
+To install this development version:
+
+1. Clone this repo locally
+2. Visit chrome://extensions/
+3. Ensure that 'Developer mode' is switched on
+4. Click "Load Unpacked"
+5. Select the PlantUML source directory
+
+To install the official version:
+
 1. Install the extension from Chrome Web Store.
 2. Check "Allow access to file URLs" in chrome://extensions/.
 3. Open local or remote text file with UML diagram definition in browser (the text starts with @startuml).
@@ -19,4 +29,4 @@ This extension does not require any permissions.
 
 ## Credits
 
-Credits go to Arnaud Roques, the author of the PlantUML. If you like this plugin, support the original author via the PayPal button on the PlantUML site (http://plantuml.sourceforge.net/index.html).
\ No newline at end of file
+Credits go to Arnaud Roques, the author of the PlantUML. If you like this plugin, support the original author via the PayPal button on the PlantUML site (http://plantuml.sourceforge.net/index.html).
diff --git a/plantuml/content-script.js b/plantuml/content-script.js
index 83a882c..98abaa9 100644
--- a/plantuml/content-script.js
+++ b/plantuml/content-script.js
@@ -1,102 +1,107 @@
-if (!document.doctype &&
-		document.documentElement.namespaceURI == 'http://www.w3.org/1999/xhtml' &&
-		document.body.textContent.substr(0, '@start'.length) == '@start') {
-	chrome.extension.sendRequest({
-		command: 'showPageAction'
-	});
-	var data = document.body.textContent;
-	var reload = true;
-	var shown = false;
-	var type = 'none';
-
-	function escapeHtml(text) {
-		return text
-			.replace(/&/g, "&")
-			.replace(/</g, "&lt;")
-			.replace(/>/g, "&gt;")
-			.replace(/"/g, "&quot;")
-			.replace(/'/g, "&#039;");
-	}
-
-	var showXhr;
-	var show = function(force) {
-		shown = shown || force;
-		if (showXhr)
-			showXhr.abort();
-
-		chrome.extension.sendRequest({ command: 'compress', data: data }, function(response) {
-			var url = [
-				response.settings.server,
-				response.settings.type,
-				response.data
-			].join('/');
-
-			switch (response.settings.type) {
-				case 'img':
-					document.body.innerHTML = ['<img id="im" src="', escapeHtml(url), '" />'].join('');
-					break;
-
-				case 'svg':
-					document.body.innerHTML = ['<img id="im" src="', escapeHtml(url), '" />'].join('');
-					break;
-
-				case 'txt':
-					document.body.innerHTML = '';
-					showXhr = new XMLHttpRequest();
-					showXhr.onreadystatechange = function() {
-						if (showXhr.readyState == 4 && showXhr.status != 404) {
-							document.body.innerHTML = ['<pre>' + escapeHtml(showXhr.responseText) + '</pre>'].join('');
-						}
-					}
-					showXhr.open('GET', url);
-					showXhr.send(null);
-					break;
-
-				default:
-				case 'none':
-					document.body.innerHTML = ['<pre>' + escapeHtml(data) + '</pre>'];
-					break;
-			}
-		});
-	}
-
-	if (location.protocol == 'file:') {
-		var xhr = new XMLHttpRequest();
-		xhr.onreadystatechange = function() {
-			if (xhr.readyState == 4 && xhr.status != 404 && (!shown || data != xhr.responseText)) {
-				data = xhr.responseText;
-				show(true);
-			}
-		};
-		var update = function() {
-			if (!shown || reload) {
-				xhr.abort();
-				xhr.open('GET', location.href + '?t=' + +new Date, true);
-				xhr.send(null);
-			}
-		};
-		setInterval(update, 1000);
-		update();
-	} else
-		show(true);
-
-	chrome.extension.onMessage.addListener(
-		function(request, sender, sendResponse) {
-			/*console.log(request);
-			var oldSendResponse = sendResponse;
-			sendResponse = function() {
-				console.log.apply(console, arguments);
-				oldSendResponse.apply(this, arguments);
-			}*/
-
-			var command = request && request.command;
-			switch (command) {
-				case 'savedSettings':
-					reload = request.settings.reload;
-					show();
-					break;
-			}
-			sendResponse();
-		}
-	);
-}
+
+if(document.body.textContent.substr(0, '@startuml'.length) == '@startuml') {
+	translateUml(document.body);
+}
+
+var c = document.querySelectorAll('code');
+var i;
+for (i = 0; i < c.length; i++) {
+    if(c[i].textContent.substr(0, '@startuml'.length) == '@startuml') {
+    	translateUml(c[i])
+    }
+}
+
+function translateUml(element) {
+	chrome.extension.sendRequest({
+		command: 'showPageAction'
+	});
+
+	var data = element.textContent;
+	var reload = true;
+	var shown = false;
+	var type = 'none';
+
+	function escapeHtml(text) {
+		return text
+			.replace(/&/g, "&amp;")
+			.replace(/</g, "&lt;")
+			.replace(/>/g, "&gt;")
+			.replace(/"/g, "&quot;")
+			.replace(/'/g, "&#039;");
+	}
+
+	var showXhr;
+	var show = function(force) {
+		shown = shown || force;
+		if (showXhr)
+			showXhr.abort();
+
+		chrome.extension.sendRequest({ command: 'compress', data: data }, function(response) {
+			var url = [
+				response.settings.server,
+				response.settings.type,
+				response.data
+			].join('/');
+
+			switch (response.settings.type) {
+				case 'img':
+					element.innerHTML = ['<img id="im" src="', escapeHtml(url).replace(/^http:/, "https:"), '" />'].join('');
+					break;
+
+				case 'svg':
+					element.innerHTML = ['<img id="im" src="', escapeHtml(url).replace(/^http:/, "https:"), '" />'].join('');
+					break;
+
+				case 'txt':
+					element.innerHTML = '';
+					showXhr = new XMLHttpRequest();
+					showXhr.onreadystatechange = function() {
+						if (showXhr.readyState == 4 && showXhr.status != 404) {
+							element.innerHTML = ['<pre>' + escapeHtml(showXhr.responseText) + '</pre>'].join('');
+						}
+					}
+					showXhr.open('GET', url);
+					showXhr.send(null);
+					break;
+
+				default:
+				case 'none':
+					element.innerHTML = ['<pre>' + escapeHtml(data) + '</pre>'];
+					break;
+			}
+		});
+	}
+
+	if (location.protocol == 'file:') {
+		var xhr = new XMLHttpRequest();
+		xhr.onreadystatechange = function() {
+			if (xhr.readyState == 4 && xhr.status != 404 && (!shown || data != xhr.responseText)) {
+				data = xhr.responseText;
+				show(true);
+			}
+		};
+		var update = function() {
+			if (!shown || reload) {
+				xhr.abort();
+				xhr.open('GET', location.href + '?t=' + +new Date, true);
+				xhr.send(null);
+			}
+		};
+		setInterval(update, 1000);
+		update();
+	} else
+		show(true);
+
+	chrome.extension.onMessage.addListener(
+		function(request, sender, sendResponse) {
+			var command = request && request.command;
+			switch (command) {
+				case 'savedSettings':
+					reload = request.settings.reload;
+					show();
+					break;
+			}
+			sendResponse();
+		}
+	);
+}