@@ -1010,7 +1010,7 @@ oldnode.parentNode.replaceChild(clone, oldNode);
10101010
10111011* javascript runs on a single thread in the browser
10121012* web workers: background thread support by the browser
1013- * only in modern browsers
1013+ * only in modern browsers (from IE 10)
10141014* you put worker code in a separate file
10151015* worker can use ```postMessage``` to send messages to the caller
10161016* caller can subscribe to messages using ```Worker.onMessage```
@@ -1038,3 +1038,32 @@ xhr.onreadystatechange = function handleResponse() {
10381038xhr.open('GET', 'page.html', true);
10391039xhr.send();
10401040```
1041+
1042+ ### JSONP
1043+
1044+ * JSON with padding
1045+ * not restricted by same origin policy (but really you should just setup CORS properly)
1046+ * callback parameter in URL specifies the JS function handling the response
1047+ * server should return data passed into the callback function as parameter
1048+
1049+ ### Image beacons
1050+
1051+ * even without javascript, data can be sent to the server
1052+ * include an img tag (typically 1x1 transpatrent PNG)
1053+ * actually better to respond with 204 No Content (old IE version might not like this)
1054+ * browser makes a request when the page is being loaded
1055+
1056+ ### combining scripts, minification, caching
1057+
1058+ * concatenate scripts to reduce number of HTTP requests
1059+ * loosing some of the granular caching benefits
1060+ * have to come up with versioning scheme
1061+ * minify to reduce script size
1062+ * use source maps to still allow easy debugging
1063+ * use cache headers properly (browsers don't cache for too long by default)
1064+
1065+ ### script tag location and attributes
1066+
1067+ * don't use language or type attribute as browsers assume JS anyways
1068+ * script tags (by default) block page loading until they're downloaded, parsed and run
1069+ * put your script tags at the bottom of the page or use HTML5 async script (since IE10)
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