Javascript: String concatenate in IE7 more than 1000 times slower than Opera!
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When writing a javascript function that returns a string built from pieces of other strings, I was wondering which was faster: Build it directly to a string or push it on an array that will be joined on return.
I wrote a little test script and tried it in Firefox 2, Opera 9 and IE7. Opera was very fast and did the string concatenate in only 0.2s. Firefox took returned after 4.1s. After 20 minutes Internet Explorer 7 still hadn’t returned!!!
This made me curios so I had to do some more testing. The result was a little surprising.
With strings Firefox was up to 17 times slower than Opera depending on the size of the data. I had to stop measuring on IE after it was more than 700 times slower than Opera.
With arrays that are joined on return Opera was the fastest one up to a certain point, then it was surprisingly IE who was the fastest one. On the largest data IE returned after only 3 seconds, FF come second with 18s and at last OP on 25s!
Below you find the results of my measurements and the javascript code used.
Chars Times IE7 string OP9 string FF2 string IE7 array OP9 array FF2 array 4000 1000 16 0 0 2000 500 16 0 0 20000 5000 78 0 0 40000 10000 16 0 47 200000 50000 4766 31 47 240000 60000 6437 31 47 320000 80000 21758 31 266 400000 100000 31 250 313 157 407 800000 200000 78 766 656 297 1250 1200000 300000 140 1579 984 485 2203 1600000 400000 187 2672 1281 641 3703 2000000 500000 235 4172 1593 812 5265 2400000 600000 2813 5828 1938 3688 7234 2800000 700000 6734 7781 2266 8000 9313 3200000 800000 11203 10016 2547 12906 12235 3600000 900000 16234 12624 2922 18671 15016 4000000 1000000 21813 15281 3204 24969 18250 // Javascript
function test_array(size) {
var s=[];
for (var i=0; i < size; ++i) { s.push("TEST");}
return s.join("");
}
function test_string(size) {
var s="";
for (var i=0; i < size; ++i) { s += "TEST";}
return s;
}
function timer(func,size) {
var start = new Date().getTime();
return func(size).length + ": " + (new Date().getTime() - start );
}
var i=100000;
alert(i + " " + timer(test_array,i));
i+=100000; alert(i + " " + timer(test_array,i));
i+=100000; alert(i + " " + timer(test_array,i));
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TRWTF is using Javascript for that much text.
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Obviously, that must have been fixed in IE8. If you won't proof the opposite, that is.
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FF3 claims to have much improved it's javascript speed. Those numbers might be interesting.
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@tster said:
FF3 claims to have much improved it's javascript speed. Those numbers might be interesting.
Here, Firefox 3 RC 3 (or so), completes this test in about 2100ms, where "100000 [concatenations] completed in 43[ms]". For comparison, IE7 completes that test in about 16000ms, where "100000 completed in 407", but the record is 469ms for a single test. IE8 seems to perform worse though, at least as far as my tests got using the linked performance test.
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Well, it seems ie7 has ripped string manipulation code from konqueror. This browser has about the same awfull results :) It's not so much important, you can't log in to thedailywtf with konqueror anyway :D
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@tchize said:
Well, it seems ie7 has ripped string manipulation code from konqueror. This browser has about the same awfull results :)
BUT KONQUEROR PASSES THE ACID3 TEST!!!
(Where IE8 is a HUGE failure. IE7 even huger!)
