ajax - JavaScript call stack -


i'm new web development , have been reading on ajax can update map live new data. i'm reading ibm article on comet. provide implementation apache tomcat.

article : http://www.ibm.com/developerworks/web/library/wa-cometjava/#resources

the javascript code provide follows..

<script type="text/javascript">             function go(){                 var url = "http://localhost:8484/weatherserver/weather"                 var request =  new xmlhttprequest();                 request.open("get", url, true);                 request.setrequestheader("content-type","application/x-javascript;");                 request.onreadystatechange = function() {                     if (request.readystate == 4) {                         if (request.status == 200){                             if (request.responsetext) {                                 document.getelementbyid("forecasts").innerhtml =  request.responsetext;                             }                         }                         go();                     }                 };                 request.send(null);             }         </script>     </head>     <body>         <h1>rapid fire weather</h1>         <input type="button" onclick="go()" value="go!"></input>         <div id="forecasts"></div>     </body>

i understand have few questions.

1) request.send() spawn new thread? 2) recursive call go() cause stack overflow?

a new thread created when request.send() unless specify explicitly not in open-method.

the call go never cause stackoverflow-exception. because called in callback , call stack reset when data returns. may recursive function, it's not. although it's defined inside go-function, execution-context different.


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