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Message-ID: <1938225.aqSPkdTlGX@PointedEars.de>
From: Thomas 'PointedEars' Lahn <PointedEars@web.de>
Reply-To: Thomas 'PointedEars' Lahn <cljs@PointedEars.de>
Organization: PointedEars Software (PES)
Date: Thu, 23 Feb 2012 22:13:05 +0100
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Subject: Re: How to write a browser based timer
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Cal Who wrote:

> "Scott Sauyet" <scott.sauyet@gmail.com> wrote […]:
>> You can certainly do what you want with Javascript.  And it shouldn't
>> be difficult.
>>
>> You need to look at three features of Javascript:
>>
>>    - Keyboard Events, to listen for the keystrokes that matter
>>    - setTimeout or setInterval to occasionally check the time
>>    - DOM manipulation to display the results

JFTR, the rather simple and proper, because reliable, approach is to call 
clearTimeout() if a timeout was set before, then setTimeout(), on keyup.  
Checking for the time that has passed since the last keypress is _not_ 
reliable by comparison.

  var timeout = null;
  
  function clearMe (timeout)
  {
    if (timeout !== null)
    {
      window.clearTimeout(timeout);
    }
  } 

  _addEventListener(control, "keyup", function () {
    clearMe(timeout);

    timeout = window.setTimeout(function () {
      /* do something */

      clearMe(timeout);
    }, 42);
  }, false);

where _addEventListener() is a wrapper for control.addEventListener() with 
proprietary event-handler properties as fallback, like 
jsx.dom.addEventListener() in JSX:event.js [1].  For a more object-oriented 
implementation of the approach mentioned before, one might want to look into 
JSX:timeout.js [2], in particular jsx.dom.timeout.Timeout.prototype.run().


PointedEars
___________
[1] 
<http://PointedEars.de/websvn/filedetails.php?repname=JSX&path=%2Ftrunk%2Fdom%2Fevents.js>
[2] 
<http://PointedEars.de/websvn/filedetails.php?repname=JSX&path=%2Ftrunk%2Fdom%2Ftimeout.js>
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