Question

Why isit when I do

http://jsfiddle.net/xe4Ph/1/

var footnoteLinks = [1,2,3];
for (var i in footnoteLinks) {
   document.write(footnoteLinks[i] + ", ");
}

What I get is something like …

1, 2, 3, function () { return lower; }, function Array() { [native code] }, function pop() { [native code] }, function push() { [native code] }, function reverse() { [native code] }, function shift() { [native code] }, function sort() { [native code] }, function splice() { [native code] }, function unshift()

Why is that? Whats with the functions etc… I think it worked ok b4, I dunno what caused this now, it seems the same for all browsers I tried. Firefox 3.6, Chrome 6 (i think?), IE9

Answer 1

The for(var in obj) is for iterating over the properties of an object. You’re getting the properties of the Array object you’ve created.

You want a more traditional looping/index construct:

for(var i=0,z=footnoteLinks.length; i<z; i++)

Some JavaScript runtimes also have map and reduce methods on Array objects, but this isn’t guaranteed. Most JavaScript libraries have something like this (or perhaps an each method), though.