Bug with multiplication in JavaScript 286.40

There seems to be a bug in Javascript using simple multiplication.

If you times 286.40 times 100 you should get 286.40 but it gives you back 286.39.9999999996.

To prove I am not crazy I have a short script that does just that.

www.myus.com/test.html

I did a search on the net and can not find any info on this.

I know how to get around it I just want to know why such a simple error has not yet been fixed within javascipt.

Or am I clueless and this is not a bug?

Im can't belive I am the first to notice this.

It only seems to do it with this number but there might be others.
Here is the test code that is at the page above.

<script type="text/javascript">
function test() {
var tmp = 0;
tmp = (286.40*100);
alert (tmp);


} // end test function
</script>
<a href="#" onClick="test();">test</a>

286.40

Check out http://www.merlyn.demon.co.uk/pas-real.htm#Float. This doesn't give an exact answer to your specific question, but it suggests that floating point numbers can be tricky. Just because something looks to us like it'd be a round number apparently doesn't mean it is in floating point arithmetic.

dhouston Thanks,


I am glad I am not going crazy.

Eddie