How to measure code execution time in VBScript or JavaScript?

Question

What is a good way to measure code execution time in VBScript ?

Or failing that how to do it in JavaScript ?

Answer 1

For VBScript you can use Timer:

StartTime = Timer()
EndTime = Timer()
Response.Write("Seconds to 2 decimal places: " & FormatNumber(EndTime - StartTime, 2))

Or ASP Profiler (that is for an ASP environment.)

For JavaScript you can use Date:

var start = new Date().getTime()
alert("Milliseconds: " + (new Date().getTime() - start))

Firebug also has a profiler for JavaScript.

Answer 2

For JavaScript, I would recommend you to use a profiler, like the one built-in in Firebug :

_{(source: getfirebug.com )}

Other alternatives can be the one included with Google Chrome , or IE8

If you want to do it programmatically, you could use Date objects to get a time difference:

var startTime = new Date();
// ...
// ...
var endTime = new Date();
var delta = endTime - startTime; // difference in milliseconds

Answer 3

Found the perfect function with proper Hours/Mins/Secs formatting here: https://social.technet.microsoft.com/wiki/contents/articles/633.vbscript-determine-script-execution-time.aspx

Usage:

dtmStartTime = Timer
Wscript.Echo "Hello, World!"
Wscript.Sleep 1000
Wscript.Echo "Script completed in " & GetElapsedTime

Function:

Function GetElapsedTime
    Const SECONDS_IN_DAY    = 86400
    Const SECONDS_IN_HOUR   = 3600
    Const SECONDS_IN_MINUTE = 60
    Const SECONDS_IN_WEEK   = 604800

    dtmEndTime = Timer

    seconds = Round(dtmEndTime - dtmStartTime, 2)
    If seconds < SECONDS_IN_MINUTE Then
        GetElapsedTime = seconds & " seconds "
        Exit Function
    End If
    If seconds < SECONDS_IN_HOUR Then 
        minutes = seconds / SECONDS_IN_MINUTE
        seconds = seconds MOD SECONDS_IN_MINUTE
        GetElapsedTime = Int(minutes) & " minutes " & seconds & " seconds "
        Exit Function
    End If
    If seconds < SECONDS_IN_DAY Then
        hours   = seconds / SECONDS_IN_HOUR
        minutes = (seconds MOD SECONDS_IN_HOUR) / SECONDS_IN_MINUTE
        seconds = (seconds MOD SECONDS_IN_HOUR) MOD SECONDS_IN_MINUTE
        GetElapsedTime = Int(hours) & " hours " & Int(minutes) & " minutes " & seconds & " seconds "
        Exit Function
    End If
    If seconds < SECONDS_IN_WEEK Then
        days    = seconds / SECONDS_IN_DAY
        hours   = (seconds MOD SECONDS_IN_DAY) / SECONDS_IN_HOUR
        minutes = ((seconds MOD SECONDS_IN_DAY) MOD SECONDS_IN_HOUR) / SECONDS_IN_MINUTE
        seconds = ((seconds MOD SECONDS_IN_DAY) MOD SECONDS_IN_HOUR) MOD SECONDS_IN_MINUTE
        GetElapsedTime = Int(days) & " days " & Int(hours) & " hours " & Int(minutes) & " minutes " & seconds & " seconds "
        Exit Function
    End If
End Function

Answer 4

对于JavaScript，请使用Firebug或IE分析器，或免费使用DynaTrace AJAX版本分析器 。

Answer 5

This really depends on what you are trying to measure?

If are testing something and want to know how long certain pieces go, you could just declare a start and stop time variable, then do a difference between them....

Answer 6

d = new Date();
x = 0;
for (i = 0; i < 1e7; ++i) { x += i; }
d2 = new Date();
d2 - d

12296

Use the Date object, which returns a valueOf() in milliseconds since Jan 1 1970. You can then subtract times to get elapsed time in milliseconds.

Answer 7

This is a great article on JavaScript timing, from the book "Even Faster Websites". Two things to keep in mind are that JavaScript Date objects often have a resolution as big as 15ms (this varies by browser and operating system), and most profilers have an observer effect . Note that Google Speed Tracer (new since the article was published) runs out of process and collects data asynchronously to minimize the observer effect.