IE charset encoding issue with JavaScript Date functions

Question

Could someone please explain why IE has a bug when trying to use String functions on a Date function that uses the "Locale"? I think it has something to do with encoding of the characters.

Check this out jsFiddle in both IE and Chrome and you will see that in Chrome we get 4 (the correct index) and in IE we get 8. Does this have to do with ascii vs. unicode? If so, should this be a bug in IE?

var date = new Date();

var str = date.toLocaleTimeString();
jQuery('#a').text(str);

jQuery('#b').text(str.lastIndexOf(":"));

str = date.toTimeString();
jQuery('#c').text(str);
jQuery('#d').text(str.lastIndexOf(":"));

Screen shot of IE 11 jsFiddle output

Screen shot of IE 11 jsFiddle output

It works perfectly well for me in IE10. What exactly does the locale time string look like in IE? — Pointy, Aug 14 '14 at 16:17

score 1 · Accepted Answer · edited May 23 '17 at 12:05

1

Here's a modified fiddle. For whatever reason, the IE 11 string has a bunch of extra Unicode "left-to-right mark" characters embedded in it.

The code I added was

var s = '';
for (var i = 0; i < str.length; ++i)
    s  += str.charCodeAt(i) + ' ';
$('#c').text(s);

and an accompanying <h4> like the others.

Also see this other Stackoverflow question on the topic.

edited May 23 '17 at 12:05

Community

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answered Aug 14 '14 at 16:26

Pointy

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So would this technically be a bug in IE 11? It just seems very annoying to have to do this encoding conversion to all these strings just because IE is incompetent. – Matt Hintzke Aug 14 '14 at 16:32
@MattHintzke well it's certainly weird, but I'm not sure you could call it a "bug". There are no firm rules on what the return value from that API should be, and there's nothing technically wrong with including those characters. (It seems dumb though.) – Pointy Aug 14 '14 at 16:33
@MattHintzke note that if you need access to the individual "pieces" of the timestamp, the Date API provides that. – Pointy Aug 14 '14 at 16:34

score 1 · Answer 2 · answered Aug 14 '14 at 16:29

By definition Date.toLocaleTimeString() produces output according to user's preferences/defaults.

So the result (position of : ) can vary on different platforms, locales and even time of the day.

This is how Korean time looks like for example:

"오후 12:00:00"

Apparently in your case Chrome and IE have different opinion on default locale formatting.

If you have any code that relies on position of : in toLocaleTimeString() it must be refactored to something more reliable.

In some locales/settings toLocaleTimeString() may not contain : at all.

IE charset encoding issue with JavaScript Date functions

2 Answers2