A javascript recursion problem

Question

I'm writing a js recursion function to find all ancestors of an element a user clicked on. my code is like this:

/**a global variable.*/
var anc; 

function getAncestors(e){  
 var ele = e.target; 
 var parentName = ele.parentNode.name;    
 anc +=bracket(parentName); 

 if (parentName.toLowerCase() == "undefined" ) return;    
 else getAncestors(parent);     
}

I ran it using firefox, but there's an error message in the error console, "Error: ele.parentNode is undefined".

also, when i reset anc = ' '; it didn't work either.

Thanks!

Paul

Where does the variable parent come from? And what does the bracket() function do? Is parent perhaps another global variable that's set by something else? — Greg Hewgill
– Greg Hewgill, Commented Oct 24, 2009 at 4:59

Justin Love · Accepted Answer · 2009-10-24 05:00:20Z

4

parent is undefined. You may have meant ele.parentNode, but see below.
By name convention and by .target, I take it e is an event. But you pass parent, which probably isn't an event.
You probably want to check that ele.parentNode is valid before getting it's properties.

answered Oct 24, 2009 at 5:00

Justin Love

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cdmckay · Accepted Answer · 2009-10-24 04:57:51Z

2

You might want to take a look at how they implement the parents function in jQuery.

answered Oct 24, 2009 at 4:57

cdmckay

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Alex Martelli · Accepted Answer · 2009-10-24 04:59:14Z

2

An undefined value, per Javascript standards, doesn't have a name attribute -- so rather than trying to get the name in one gulp, just do a var parent = e.target.parentNode; and bail out if THAT is undefined!

answered Oct 24, 2009 at 4:59

Alex Martelli

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Xinus · Accepted Answer · 2009-10-24 05:10:58Z

0

You should break the recursion like this

if(ele.parentNode) return;

parentNode.name is not supported by firefox

answered Oct 24, 2009 at 5:10

Xinus

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1 Comment

Justin Love Over a year ago

That should be negated (if (!ele...), yes?

Nick Jurista · Accepted Answer · 2009-10-24 05:11:27Z

0

Maybe try something like this:

var anc = [];

function getAncestors(element) {
  if (element.parentNode) {
    anc.push(element.parentNode);
    getAncestors(element.parentNode);
  }
}

answered Oct 24, 2009 at 5:11

Nick Jurista

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