Microsoft goes deep inside IE in Windows 10 to explore Chakra JavaScript improvments

Microsoft gets highly technical in their latest Internet Explorer blog post that describes the improvements that have been put into the Chakra JavaScript engine in Internet Explorer for the Windows 10 Technical Preview.

Most of this blog is not for the ordinary layman but it's still a fascinating look at how Microsoft has tried to improve IE for Windows 10. Here's an example that describes a new method in IE for faster performance when loading websites and apps.

"Starting with Windows 10 Technical Preview, Chakra now has an additional JIT compilation tier called Simple JIT, which comes into play in-between the switch over from executing a function in the interpreter to executing the highly optimized JIT code, when the compiled code is ready. As its name implies, Simple JIT avoids generating code with complex optimizations, which is dependent on profile data collection by the interpreter. In most cases, the time to compile the code by the Simple JIT is much smaller than the time needed to compile highly optimized JIT code by the Full JIT compiler. Having a Simple JIT enables Chakra to achieve a faster switchover from bytecode to simple JIT'ed code, which in turn helps Chakra deliver a faster startup for apps and sites.

Remember, this is just the preview build of IE in Windows 10. Microsoft is holding off on releasing the full version of Internet Explorer 12 until sometime in the future. In the meantime, what do you think about Microsoft's efforts to improve performance in IE via this preview build?

Source: IE blog (opens in new tab)

John Callaham
  • Good going Microsoft (: (y)
  • Yeah, good going... This is why other browsers are ahead... MS's always outlining their tricks to the public... Lol!
  • I know you're joking, but in actual fact other browsers are not ahead in terms of JavaScript speed. IE is miles ahead of the rest ever since v9 when they switched to HW-accelerated JavaScript.
  • Well good not sure but why should I give about JavaScript when other browser performs and function vastly superior if its already is fast should they improve a lot of other features and functions everything seems age old what's good is a good engine without a good suspension and or flat tire.....i want improvements in UI and more features!
  • IE is miles BEHIND others.  I know because my MVC pages using jQuery run the slowest on IE.  Chrome is the best and Firefox the 2nd.
  • Potentially you're experiencing memory issues here, which IE does seem to have (though I've noticed this has improved massively in Windows 10). However IE's raw JavaScript speed is much faster than Chrome: about 1.5x in IE11 and 2x in Windows 10, according to the SunSpider benchmark created by Webkit to test JavaScript speed in real-world usage scenarios.
  • Miles ahead... That's not what the average consumer says, and not what benchmarks say either.
  • It is nice to see that MS is trying to improve IE. Even though IE having some performance issues still I am using it for most of the time.
  • "is not for the ordinary layman"... Hence, my opinion is: what?
  • Seems faster
  • I will biach slap you, NIST.
    Lumia 1040.
  • Lol. What?
  • Lol!!!!
  • AGAIN another improvement towards the startup time of websites and to interact. For years now IE has suffered from this issue that scrolling is unresponsive until most elements load on the site. When Windows 8 introduced smooth scroll system wide I thought it would be just as great as on OSX but nope many sites are still terribly slow and even though smooth scrolling is there, at startup it just doesn't response to scrolling.
  • Yes, that is very irritating.
  • it won't matter. people hate IE. this is how to fix it: 1) keep IE for enterprise and rename the product for consumers. Start fresh with a new UI that is modern, lean, all cloud enabled and with a robust plugin and extension model. 2) embrace HTML5 all the way including all the stuf webkit has. push updates the way chrome does for really fast iteration. As this is consumer IE, enterprise stays safe in the glaciar ages they enjoy. 3) eat humble pie. collaborate with mozilla to offset chrome's stablishment. label chrome the new IE, bloated, propietary, full of google bloatware. Embrace mozilla's plugin architecture so devs can port their work to IEvnext without re-learing the system. I'd even say take trident, toss it out and embracke gecko in a collaboration with mozilla to keep the web open and free of all teh <webkit> markup. then again lol, this is microsoft we're talking about. IE will remain the same. mocked. hopeless. even if it is a decent browser.
  • Actually people hate IE with a reason.  To fix it its simple: FIX IE. I hate google, i tried many times using IE before Chrome but in the end... CANT DO IT.   Same thing with, its a "good effort" but in the end Gmail is still better. Same thing with OneDrive.  Its a good cloud, but Gdrive is 5x faster. Search on the internet and you will see tons of speed issues with OneDrive and MS wont accept it. Same thing with Bing maps.  Its good but some streets missing names, isnt even close to gmaps to find the address you type in... Same thing with GOOGLE over Bing.  Simple searches are even but complex ones Bing cant match Google. Actually, Nadella, FIX MS. Ballmer did a terrible job, really.
  • You're right. Outlook and OneDrive might look beautiful, but they are VERY slow compared to the same services from Google.
  • Haha....good summary.
    I do use OneDrive, but it is horribly slow. I do actually prefer IE is an absolute dog though...and Bing maps are very average!
    Damn those Google people. They may track me relentlessly across the web, but they do have a good set of services.
  • How is drive and Gmail better than Outlook and OneDrive?
  • WTF hahahahha
    use here drive,
    use IE11 or FIREFOX... prefer help firefox, over that google shit!
    outlook is secure and onedrive is not slow, and i am talikng in Brazil right now...  
  • I do use Here Drive!  But Gmaps still beats Bing Maps... The point is... Microsoft needs to improve their products badly. I have an XBOX One, Windows Phone, Windows Tablet, Windows Desktop... but i cant watch any movies i made with my Windows Phone in XBOX because OneDrive is REALLY bad and XBOX does a terrible job with caching and preloading the videos, it "Just doesnt work"  very oppose to what Apple sells... If you set xbox to USA region you can buy the same game for half the price of the brazilian store so what do you do ?  you change to USA region.  I got my gold membership in USA region.  Then i wanted to get xbox music and found out that it doesnt work.  It works on xbox but not in Windows Phone.  xbox support says that it is all fine in their side so probably region issues and thats my problem. Well i have news for them too, Spotify "Just works"... same price, same musics, just need an xbox app and there is really no reason to xbox music exist. Besides, as a programmer, if i wanted to make a really really bad app like xbox music for Windows Phone i would have to sit for days and design it that way. Really... if i just started programming something to be a music app without any good thoughts it would still be better than xbox music! I do like microsoft, i am a big fan of Bill Gates, we cant compare him to Steve Jobs or Sergey... it would be unfair, almost an insult to the kind of person he became compared to the others.  But his company needs to start improving the quality of their services.  i hope Nadella does that!
  • Peeps be trolling
  • Do a video search on both. Come back and tell us how great Google is.
  • is great. Then what??
  • Ok...WHY was Google video search "great"?
  • IE need some refinement. I have not been using any other web browser besides IE for more than a year now. I see the improvements but I'd like web sites like and to work better. I usually get " running long script" notification which literally kills my browsing experience. But I still hope to see better.
  • Awesome
  • Seems faster
  • Chakra JavaScript...hmm...Nadella named it?
  • Not quite...
  • No.masahi hsimito (Naruto creater) lol
  • So slow... :(
  • IE needs speed dials for ducks sake
  • & proper plugins like the Chrome Store
  • And an Opera like password manager
  • And a button to reopen last closes pages.
  • Hey everyone. As I don't install the W10 yet, what is the result of IE12 preview on ? Thanks :-)
  • 376
  • It's not IE12.  It's mostly IE11 still.
  • Thanks guys for the answer.
  • What most commenters are missing is that this means Windows Store Apps written in Javascript will launch and run faster (example: the Windows Store app runs on javascript so it should start faster and run smoother in slower devices like the first surface rt).
  • "Improvment"?
  • As in improv. Just making crap up.
  • Generally not a fan of JIT, but in Internet browsing its utterly unavoidable. Microsoft have done JIT right. I likey the new one.
  • If this fixes the issues with IE then great. I admittingly use IE and I like it, but god is it slow. Even this website takes forever to load and for me to scroll down the page. I feel like the IE on our phones is better than the desktop version.
  • I must say IE is faster than chrome especially in startup time, and much better optimized for touch... While Chrome is a memory monster, extensions are what makes it standout . In the mean while, IE do need a better UI and extension framework
  • As much as I dislike IE, it doesn't cause my PC to beg for death like chrome does
  • I do love to use IE since IE10, it has been much smoother and faster. But I still can't help ignoring the unresponded scrolls which happen so often. And things I hate the most in IE is its stupid bookmark and sync.
  • Improvements* (article title)
  • IE 11 is amazing for sure IE 12 will be stunning
  • Internet Explorer needs a redesign. Better management of settings, favourites, passwords, history, ...
  • I don't know if it is too late