320093 - In javascript 0.7+0.2=0.8(9)

Status: RESOLVED DUPLICATE of bug 5856

(Core :: JavaScript Engine, defect)

Description

[Viktor Yarmak]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051111 Firefox/1.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051111 Firefox/1.5

Invalid handling of mathematical operations: 0.7+0.2=0.8(9)


Reproducible: Always

Steps to Reproduce:
1. Create new document with javascript "alert(0.7+0.2);" or open a javascript console and put alert(0.7+0.2); to evaluate

Actual Results:  
0.8999999999999

Expected Results:  
I expect that result will be 0.9!!! :)

Comment 1

[Elmar Ludwig]

*** This bug has been marked as a duplicate of 5856 ***

Comment 2

[Brendan Eich [:brendan]]

See my blog item at http://weblogs.mozillazine.org/roadmap/archives/008325.html -- obviously we would help a number of users by somehow switching to decimal mode arithmetic.  The problem is backward compatibility.  If you are willing to write a pragma (JS2/ECMAScript Edition 4 proposed syntax):

    use arithmetic decimal;

then you'd be all set in the rest of the script in which that pragma occurred.

/be