Never use a for..in loop to iterate over an array.
Without seeing the code in the context of a running test page, I can't tell
you why IE is seeing a bogus element in the array, but I can speculate that
some other code elsewhere in the page is adding a method to Array.prototype
in IE only. That method would be enumerated during the for..in loop.
You can fix this by using a proper technique to loop through the array. You
could use $.each, or a "for( i = 0, n = data.length; i < n; i++ )" loop.
Or, since you know the array doesn't contain any null elements, here's my
favorite technique (along with a couple of other minor improvements):
function loadResults(data) {
var OPT_VOTES = 2;
var total_votes = 0;
for( var item, i = -1; item = data[++i]; ) {
votes = +item[OPT_VOTES];
total_votes += votes;
alert( "total_votes=" + total_votes + " --- " + votes );
}
}
-Mike
_____
From: Bruce MacKay
Hi folks,
The following snippet processes a JSON string sent back to the browser (it
is part of a poll)
function loadResults(data) {
var OPT_VOTES = 2;
var total_votes = 0;
for (id in data) {
total_votes = total_votes+parseInt(data[id][OPT_VOTES]);
alert("total_votes="+total_votes+" --- " +
data[id][OPT_VOTES]);
}
}
The JSON string looks like this...
[["1","High cost","23","What
is the biggest challenge to recycling irrigation
water?"],["2","Disease and algae
management","12","5"],["3","Plentiful
and cheap water","8","4"]]
The problem I'm having is that IE7 appears to see 4 rows in the array - and
consequently returns "total_votes=NaN --- undefined" at the first alert and
"total_votes=NaN --- 23" at the second loop and so on.
FF, Opera, and Safari all handle the code without problem - can anyone help
me understand what IE7 is getting upset about?
Thanks,
Bruce
