Added Numbers in pageAction icon and added content script.

.gitignore

@@ -1 +1,2 @@
 *.svg
+printed.png

webextension/background.js

@@ -1,16 +1,57 @@
-console.log("background");
+var getPageActionIcon = function(){
+	var faktor = 2;
+	var canvas = document.createElement("canvas");
+	canvas.width = canvas.height = 19 * faktor;
+	var context = canvas.getContext("2d");
+	var img = document.createElement("img");
+	img.src = "icons/printed" + (19 * faktor) + ".png"
+	
+	
+	return function getPageActionIcon(c){
+		context.clearRect(0, 0, canvas.width, canvas.height);
+		context.drawImage(img, 0, 0, canvas.width, canvas.height);
+		if (c > 1){
+			context.fillStyle = "#000000";
+			context.fillRect(9 * faktor, 9 * faktor, 10 * faktor, 10 * faktor);
+			context.strokeStyle = context.fillStyle = "#FFFFFF";
+			context.textAlign = "center";
+			context.textBaseline = "middle";
+			context.font = "Bold " + (10 * faktor) + "px Arial";
+			context.fillText(c < 10? c: ">", 14 * faktor, 15 * faktor);
+		}
+		return context.getImageData(0, 0, canvas.width, canvas.height);
+	}
+}();
+
+function updatePageActionIcon(tabId, c){
+	if (c === 0){
+		browser.pageAction.hide(tabId);
+	}
+	else {
+		browser.pageAction.show(tabId);
+		browser.pageAction.setIcon({
+			tabId: tabId,
+			imageData: getPageActionIcon(c)
+		});
+	}
+}
+
+var c = 0;
+
 browser.tabs.query({}).then(function(tabs){
-	console.log("tabs", tabs);
 	tabs.forEach(function(tab){
-		console.log("tab", tab);
-		browser.pageAction.show(tab.id).then(function(){console.log("success");}, function(){console.log("error");});
+		browser.pageAction.show(tab.id);
 	});
 });
 
-browser.tabs.onActivated.addListener(function(tab){
-	browser.pageAction.show(tab.id);
+browser.tabs.onActivated.addListener(function(activeInfo){
+	c += 1;
+	// console.log(c);
+	updatePageActionIcon(activeInfo.tabId , c);
 });
-browser.tabs.onUpdate.addistener(function(tab){
-	browser.pageAction.show(tab.id);
+browser.tabs.onUpdated.addListener(function(tabId){
+	// c += 1;
+	//console.log(c);
+	// updatePageActionIcon(tabId, c);
 });
 	

webextension/contentScript.js

@@ -0,0 +1,8 @@
+var oldAlert = alert;
+exportFunction(
+	function(str){
+		oldAlert("From page script: " + str);
+	},
+	window,
+	{defineAs:'alert'}
+);

webextension/manifest.json

@@ -14,6 +14,13 @@
 		},
 		"default_popup": "pageAction/index.html"
 	},
+	"content_scripts": [
+		{
+			"matches": ["<all_urls>"],
+			"js": ["contentScript.js"],
+			"run_at": "document_start"
+		}
+	],
 	
 	"applications": {
 		"gecko": {