Better way of getting time in milliseconds in javascript

Question

Is there an alternative in JavaScript of getting time in milliseconds using the date object  or at least a way to reuse that object  without having to instantiate a new object every time I need to get this value  I am asking this because I am trying to make a simple game engine in JavaScript  and when calculating the  delta frame time   I have to create a new Date object every frame  While I am not too worried about the performance implications of this  I am having some problems with the reliability of the exact time returned by this object   I get some strange  jumping  in the animation  every second or so  and I am not sure if this is related to JavaScript s Garbage Collection or a limitation of the Date object when updating so fast  If I set the delta value to some constant  then the animation if perfectly smooth  so I am fairly sure this  jumping  is related to the way I get the time   The only relevant code I can give is the way I calculate the delta time    prevTime   curTime  curTime    new Date    getTime    deltaTime   curTime - prevTime    When calculating movement   animation I multiply a constant value with the delta time   If there is no way to avoid getting the time in milliseconds by using the Date object  would a function that increments a variable  being the elapsed time in milliseconds since the game started   and which is called using the SetTimer function at a rate of once every milliseconds be an efficient and reliable alternative    Edit   I have tested now my code in different browsers and it seems that this  jump  is really only apparent in Chrome  not in Firefox  But it would still be nice if there were a method that worked in both browsers

User · Answer

I know this is a pretty old thread  but to keep things up to date and more relevant  you can use the more accurate performance now   functionality to get finer grain timing in javascript   window performance   window performance        performance now    function         return performance now                  performance mozNow               performance msNow                performance oNow                 performance webkitNow                        Date now    none found - fallback to browser default

User · Answer

As far that I know you only can get time with Date   Date now is the solution but is not available everywhere   https   developer mozilla org en JavaScript Reference Global Objects Date now   var currentTime    new Date      This gives you the current time in milliseconds   For your jumps  If you compute interpolations correctly according to the delta frame time and you don t have some rounding number error  I bet for the garbage collector  GC    If there is a lot of created temporary object in your loop  garbage collection has to lock the thread to make some cleanup and memory re-organization   With Chrome you can see how much time the GC is spending in the Timeline panel   EDIT  Since my answer  Date now   should be considered as the best option as it is supported everywhere and on IE    9

User · Answer

This is a very old question - but still for reference if others are looking at it - requestAnimationFrame   is the right way to handle animation in modern browsers   UPDATE   The mozilla link shows how to do this - I didn t feel like repeating the text behind the link

User · Answer

If you have date object like  var date   new Date  2017 12 03      then there is inbuilt method in javascript for getting date in milliseconds format which is valueOf    date valueOf      1512239400000 in milliseconds format

User · Answer

Try Date now     The skipping is most likely due to garbage collection  Typically garbage collection can be avoided by reusing variables as much as possible  but I can t say specifically what methods you can use to reduce garbage collection pauses

[javascript] Better way of getting time in milliseconds in javascript?

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