Ajax Bestiary » performance http://www.ajaxbestiary.com AJAX Development, News, Techniques & More Wed, 01 Feb 2012 12:46:54 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Implicit Vs. Explicit Conversion in Javascript http://www.ajaxbestiary.com/2008/01/14/implicit-vs-explicit-conversion-in-javascript/ http://www.ajaxbestiary.com/2008/01/14/implicit-vs-explicit-conversion-in-javascript/#comments Mon, 14 Jan 2008 13:13:59 +0000 Don Albrecht http://www.ajaxbestiary.com/2008/01/14/implicit-vs-explicit-conversion-in-javascript/

A question emerged out of my boredom on my flight yesterday.  Which is faster, implicit vs explicit conversion.  Most javascript developers use implicit conversion out of habit. For example:

!!x; instead of Boolean( x ); and x + “”; instead of String( x);. 

I decided to try an experiment for myself and record the performance of casting a number to a Boolean or String on my Windows box in Safari 3, Firefox 2, Opera 9 and IE 7.

The Verdict:

Implicit conversion wins handily, demonstrating over a 7 fold performance increase in one test. Overall, the performance gain for using implicit conversion averaged out to 53% across browsers after 10 tests.

The Numbers:

  Implicit Boolean Explicit Boolean Implicit String Explicit String
Firefox 2 0.162 0.312 0.248 0.358
IE 7 0.042 0.100 0.074 0.152
Opera 9 0.030 0.088 0.020 0.142
Safari 3 0.028 0.036 0.074 0.100
Cross Browser Average 0.066 0.134 0.104 0.188

You can find the code I used after the jump.

The Code:

<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01 Transitional//EN”>
<html>
  <head>
  <meta http-equiv=”content-type” content=”text/html; charset=windows-1250″>
  <meta name=”generator” content=”PSPad editor, www.pspad.com”>
  <title></title>
  <script type=”text/javascript”>
  // JavaScript Document

var implicitBoolean, explicitBoolean, implicitString, explicitString, startDate, endDate;

implicitBoolean = explicitBoolean = implicitString = explicitString = 0;

for( i = 0; i < 500; i++ ){

startDate= new Date();
for( i=0; i < 32000; i++){ Boolean( i );}
endDate = new Date();
explicitBoolean += ( endDate – startDate );
startDate= new Date();
for( i=0; i < 32000; i++){ !!i;}
endDate = new Date();
implicitBoolean += ( endDate – startDate );

startDate= new Date();
for( i=0; i < 32000; i++){ String( i );}
endDate = new Date();
explicitString += ( endDate – startDate );

startDate= new Date();
for( i=0; i < 32000; i++){ i + “”;}
endDate = new Date();
implicitString += ( endDate – startDate );
}

document.writeln( “Implicit Boolean:  ” + (implicitBoolean / 500 ) + “<br />” );
document.writeln( “Explicit Boolean:  ” + (explicitBoolean / 500 ) + “<br />” );
document.writeln( “Implicit String:  ” + (implicitString / 500 ) + “<br />” );
document.writeln( “Explicit String:  ” + (explicitString / 500 ) + “<br />” );
  </script>
  </head>
  <body>

  </body>
</html>

]]> http://www.ajaxbestiary.com/2008/01/14/implicit-vs-explicit-conversion-in-javascript/feed/ 2 FastInit: SuperCharge Your Pageloads http://www.ajaxbestiary.com/2007/11/27/fastinit-supercharge-your-pageloads/ http://www.ajaxbestiary.com/2007/11/27/fastinit-supercharge-your-pageloads/#comments Tue, 27 Nov 2007 14:47:31 +0000 Don Albrecht http://www.ajaxbestiary.com/2007/11/27/fastinit-supercharge-your-pageloads/

What is it:

FastInit is a small JS file to create a Faster window.onload. It implements a powerful onload function queue that fires once teh dom is ready and before all images have been downloaded. Ideally, this results in a dramatic decrease in a pages initialization time.

How it Works

You any functions to the queue by using the FastInit.addOnLoad( function 1, function 2, …); function. All functions are fired in the order in which they were added to the queue. addOnLoad can be called as many times as is necessary. It fails gracefully to standard handlers if the browser doesn’t support the faster methods.

Requirements

As of version 1.4.1 the need for Prototype has been removed freeing the code for use in any project where a speedy onload method is needed.

Check it out here:

http://tetlaw.id.au/view/javascript/fastinit

]]> http://www.ajaxbestiary.com/2007/11/27/fastinit-supercharge-your-pageloads/feed/ 0 Streamline Your Javascript with Shorthand http://www.ajaxbestiary.com/2007/11/02/streamline-your-javascript-with-shorthand/ http://www.ajaxbestiary.com/2007/11/02/streamline-your-javascript-with-shorthand/#comments Fri, 02 Nov 2007 12:19:55 +0000 Don Albrecht http://www.ajaxbestiary.com/2007/11/02/streamline-your-javascript-with-shorthand/

D’bug has published a wonderful list of techniques for abbreviating Javascript and improving performance.

You can find the article here:

http://blog.reindel.com/2007/11/01/javascript-shorthand-tips-and-tricks/

]]> http://www.ajaxbestiary.com/2007/11/02/streamline-your-javascript-with-shorthand/feed/ 0