Problem with passing Arg with setInterval()

**jens1701** · 11-05-2007 08:03 AM

Hi,

i tried to pass an Object as an argument to a function that is periodical invocated by a setInterval() function. But the passing only worked on the inital invocation, in all that follow the arg is 'undefined'.
The synopsis i used:

Code:

obj.active = window.setInterval("colorChange()", 1000, obj);

The error console tells me that the error is in that line of the function, that uses the obj for the first time. So i asume the obj was not passed.

Code:

Fehler: obj has no properties

I don't know what i did wrong, please give me a hand and look into this.

Greets

Jens

Here the whole example:

Code:

<?xml version="1.0" encoding="iso-8859-1" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
	"http://www.w3.org/chtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html; iso-8859-1"/>

<script type="text/javascript"> 
/* <! [Cdata[ */
	
function colorChange(obj) {
 	 	 	 	
 	 if (obj.currentColor == 1) {
    	document.bgColor = obj.bgColor[1];
    	obj.currentColor = 2;
  	} else {
    	document.bgColor = obj.bgColor[0];
   		obj.currentColor = 1;
  	  }
  	  
 	obj.currentCount += 1;
 	
  	if (obj.currentCount >= obj.maxChanges)
  		window.clearInterval(obj.active);
  	
  	if(!obj.active) {
  		obj.active = window.setInterval("colorChange()", 1000, obj);
  	}
    
}

window.onload = function() {
	
	document.getElementById('startTheMess').onclick = function() {
		var Color = {};
		Color.maxChanges = 10;
		Color.currentCount = 1;
		Color.bgColor = ['yellow', 'aqua'];
		Color.currentColor = 1;
		Color.toString = function() {
			return 'Object: Color maxChanges = '+Color.maxChanges+', currentCount = '+Color.currentCount+', bgColor = '+Color.bgColor;
		}
		
		colorChange(Color);	
	}
}

/* ]]> */
</script>

</head>
<body>

<h1>Color change with setInterval()</h1>
<h3>Synopsis</h3>
<p>window.setInterval(func, interval, args...)</p>
<h3>Arguments</h3>
<p>func: A javascript function to be periodically executed</p>
<p>interval: in milli sec (integer) </p>
<p>args: Any number of arbitrary values to be passed as arguments to each invocation of the func.</p>

<h2 id="startTheMess">start</h2>

</body>

</html>

And my debuggin output:

Code:

level 1: calling colorChange(Object: Color maxChanges = 10, currentCount = 1, bgColor = yellow,aqua)
level 2: count: 2
level 2: active set
level 1: calling colorChange(undefined)
level 1: calling colorChange(undefined)
...

**jens1701** · 11-05-2007 11:44 AM

I looked into it some more, so i can ask that question more specific.

Is it possible to pass arbitrary args to a function invoked by setInterval():

like this??

Code:

var active = window.setInterval('ANIMATION.animator()', aniObject.timing, aniObject);

or is there an other way to do that?

Greets

Jens

**Kor** · 11-06-2007 04:45 AM

You may use an anonymous

Code:

obj.active = window.setInterval(function(){colorChange(obj)}, 1000);

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