Closed
Bug 82706
Opened 25 years ago
Closed 25 years ago
Bad performance of JavaScript Engine, especially when manipulating the DOM
Categories
(Core :: JavaScript Engine, defect)
Tracking
()
People
(Reporter: Erich.Iseli, Assigned: rogerl)
Details
(Keywords: perf)
I ran a few tests:
1) increment a variable 1 million times
2) createElement 10,000 times
3) appendChild 10,000 times
Based on these, I was surprized to see that already in test 1, Mozilla is 3.5
times slower than IE. In Test 2, this number increased to 5.5 times slower. But
when I performed test 3, I just couldn't believe it: I first thought the
browser was frozed when after 28 seconds, the browser responded again... IE
does the same task in 1 second. So here (very complicated math...) we are 28
times slower than IE.
Of course I know you never really do such things, you create 10, 20 elements,
and then everything happens quite fast. But the fact is, Mozilla is slower.
This is not a rant, so please don't flame me. I didn't find another similar bug
report, but I don't exclude the possibility this one is a dupe.
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Reporter | |
Comment 1•25 years ago
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I wanted to post the script as Attachment, but due to some firewall
restrictions in my company, it didn't get through, so here it is:
<html>
<head>
<title>Test</title>
<script type="text/javascript">
function init() {
myHome = document.getElementById("home");
var first = new Date();
var start = first.getMilliseconds()+(first.getSeconds()*1000)+(first.getMinutes
()*60000);
for (i=0;i<10000;i++) {
newDiv = document.createElement("div");
myHome.appendChild(newDiv);
}
var last = new Date();
var end = last.getMilliseconds()+(last.getSeconds()*1000)+(last.getMinutes()
*60000);
alert("It took "+(end-start)/1000+" seconds to create 10,000 divs.");
}
</script>
</head>
<body id="home" onload="init()">
</body>
</html>
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Comment 2•25 years ago
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To show you that this is not only a benchmark thing, but can also be noticed on
some web sites: try the JavaScript menu on http://www.arcor.net with IE and
Mozilla. Notice how slow it is with Moz compared to IE.
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Comment 4•25 years ago
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Marking Verified Duplicate.
FWIW, here are timings I got from "1) increment a variable 1 million times".
Actually, the following HTML allows you to choose the number of iterations
yourself:
<html>
<head>
<title>Bug 82706</title>
<script type="text/javascript">
function init()
{
var UBound = prompt("How many iterations would you like to run?");
var start = new Date();
for (i=0; i<UBound; i++)
{
}
var duration = new Date() - start;
alert(duration + " ms");
}
</script>
</head>
<body onload="init();">
<P><B>Testing how long it takes to increment a variable in JavaScript -</B>
</body>
</html>
RESULTS (in milliseconds).
Using Mozilla binary 2001052206 on WinNT:
10^3 10^4 10^5 10^6
IE4.7 0-16 32 266 2656
NN4.7 63 640 6300 62860
Mozilla 0-16 109 1078 10875
So on this pure JavaScript, Mozilla seems about 4 times slower
than IE4.7, but 6 times faster than NN4.7.
Status: RESOLVED → VERIFIED
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Description
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