Function check: why gives IE an error and firefox not???

This gives an error in IE

function x() {

length = getPathLength();

}


function getPathLength() {
//return the length of the path
	var num = polyPoints.length;

	if(num > 1){
	var ret = 0;
	for(var i = 0; i < (num-1); ++i){
		  ret += polyPoints[i].distanceFrom(polyPoints[i+1]);
	}
		ret = ret.toFixed(3)/1000;
		return ret;
	}
  return NaN;
}

Code (markup):

I know length = getPathLength(); gives me the error in IE, because if i deleted that part it doesn't show an error.

Any tips??

 

What exactly is "polyPoints"? You're getting an error cause "polyPoints" is undefined...

 

no, that's properly not it.

polyPoints is a global var.

Like i said if i delete

length = getPathLength(); 

Code (markup):

from the function i get no errors

Any other thoughts?

 

Can you fill in the rest of the script including the (assuming html) that calls it. At a guess I'd say that the reason you don't get an error when you remove that line of code is because the function is only called from that line of code. Generally speaking firefox is much more forgiving that IE.

 

Try i++ instead of ++i

I believe in the very first iteration of your loop i will be 1 not 0,
so that in your last loop i = num (because you are pre-incrementing i before entering loop.

you evaluate i < (num - 1) then immediatly increment i.

i++ says do the loop then increment me.
++i says increment me then to loop

Anyway, this code looks familiar.
Aren't you also going to want an if statement in the loop

like

if( i == (num - 1))
ret += polyPoints.distanceFrom(polyPoints[0]);
else
ret += polyPoints.distanceFrom(polyPoints[i+1]);

that will compute the total boundry length if your points are stored in order (say...clockwise direction)