WebWorkers example with two way messages.

- Prime number background worker that can be started, stopped and reset that calculates prime numbers and sends them back to the main page/thread.

WebWorkers example with two way messages.
- Prime number background worker that can be started, stopped and reset that calculates prime numbers and sends them back to the main page/thread.
d628147b · Joel Martin · 85b7a7d4 · d628147b · d628147b
Commit d628147b authored Apr 10, 2010 by Joel Martin
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prime.html prime.html +40 -0

prime.js prime.js +39 -0

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--- a/prime.html
+++ b/prime.html
+<!DOCTYPE HTML>
+<html>
+ <head>
+  <title>Worker example: One-core computation</title>
+ </head>
+ <body>
+  <p>The highest prime number discovered so far is: <output id="result"></output></p>
+  <input type='button' value="Start" onclick="worker.postMessage('start');">
+  <input type='button' value="Stop" onclick="worker.postMessage('stop');">
+  <input type='button' value="Reset" onclick="worker.postMessage('reset');">
+  <br>
+  Log:<br>
+  <textarea id='debug' style="font-size: 9;" cols=80 rows=25></textarea>
+  <script src="include/mootools.js"></script>
+  <script src="include/mootools-more.js"></script>
+  <script>
+    function debug(str) {
+        cell = $('debug');
+        cell.innerHTML += str + "\n";
+        cell.scrollTop = cell.scrollHeight;
+    }
+
+    debug('Starting');
+
+    var worker = new Worker('prime.js');
+    worker.onmessage = function (event) {
+        var cmd = event.data.substr(0,4);
+        var data = event.data.substr(4);
+        switch (cmd) {
+            case 'log:':
+                debug(data);
+                break;
+            case 'num:':
+                $('result').innerHTML = data;
+                break;
+        }
+   };
+  </script>
+ </body>
+</html>
--- a/prime.js
+++ b/prime.js
+var n = 1;
+var cur = 1;
+var timer = null;
+
+function search() {
+    if (timer) clearTimeout(timer);
+    var sqrtn = Math.sqrt(n);
+    for (iters = 0; iters < 10000; iters += 1) {
+        cur += 1;
+        if ((cur <= sqrtn) && (n % cur != 0)) continue;
+        if (cur > sqrtn) {
+            postMessage("num:" + n);
+        }
+        n += 1;
+        cur = 1;
+    }
+    timer = setTimeout(search, 10);
+}
+
+
+onmessage = function (e) {
+    switch (e.data) {
+        case 'start':
+            postMessage("log:start");
+            if (timer) clearTimeout(timer);
+            timer = setTimeout(search, 100);
+            break;
+        case 'stop':
+            postMessage("log:stop");
+            if (timer) clearTimeout(timer);
+            started = false;
+            break;
+        case 'reset':
+            postMessage("log:reset");
+            n = 1;
+            postMessage('num:');
+            break;
+    }
+}