HTML5 ? ???
HTML5 ? ??
? ??? ??????? ???? JavaScript?? ??? ??? ??? ?? ????.
?????
HTML ????? ????? ??? ? ????? ??? ??? ??? ??? ???? ????.
? ??? ?? ????? ????? ??????? ???? JavaScript?? ??? ??? ??? ??? ????. ? ???? ??????? ???? ?? ??, ?? ? ??? ??? ??? ? ????.
????? Web Worker? ????? ??
Web Worker? ???? ?? ???? ????? ?? ????? ?????.
if(typeof(Worker)!=="undefined")
{
// Yes! Web worker support!
// Some code.....
}
else
{
// Sorry! No Web Worker support..
}? ??? ?? ??
?? ?? JavaScript?? ? ???? ??? ?????.
??? ?? ????? ?????. ????? "demo_workers.js" ??? ?????:
var i=0;
function timedCount()
{
i=i+1;
postMessage(i);
setTimeout("timedCount()",500);
}
timedCount();? ???? ??? ??? postMessage() ??????. ? ???? ???? HTML ???? ?? ??? ? ?????.
??: ? ??? ????? ??? ??? ?????? ???? ?? CPU ???? ???? ?????.
? ??? ?? ???
?? ? ??? ??? ???? ?? HTML ????? ???? ???. /p>
?? ??? ???? ????? ??? ????, ???? ?? ?? ? ? ??? ??? ??? ?? "demo_workers.js"?? ??? ?????: /p>
if(typeof(w)=="undefined")
{
w=new Worker("demo_workers.js");
} ?? ?? ? ?????? ???? ??? ?? ? ????.
? ???? "onmessage" ??? ???? ?????.
w.onmessage=function(event){
document.getElementById("result").innerHTML=event.data ;
};
<p web="" Worker=""? ???? ???? ??? ???? ??? ?????. event.data=""?? ="" event.data=""? ???? ???? ????.
Web Worker ??
? ??? ??? ???? ??? ??? (?? ????? ??? ???) ???? ???? ?????.
? ???? ???? ????/??? ???? ????? quit() ???? ??????:
w.terminate();
?? Web Worker ?? ??
??? .js ???? Worker ??? ??????. HTML ???? ??? ??? ????.
?
<!DOCTYPE html>
<html>
<body>
<p>計數(shù): <output id="result"></output></p>
<button onclick="startWorker()">開始計數(shù)</button>
<button onclick="stopWorker()">停止計數(shù)</button>
<br><br>
<script>
var w;
function startWorker()
{
if(typeof(Worker)!=="undefined")
{
if(typeof(w)=="undefined")
{
w=new Worker("demo_workers.js");
}
w.onmessage = function (event) {
document.getElementById("result").innerHTML=event.data;
};
}
else
{
document.getElementById("result").innerHTML="Sorry, your browser does not support Web Workers...";
}
}
function stopWorker()
{
w.terminate();
}
</script>
</body>
</html>
