Closed Bug 553799 Opened 14 years ago Closed 14 years ago

unknown JavaScript calculate error

Categories

(Firefox :: General, defect)

Product:
Firefox
Component:
General
Platform:
x86
Windows 7
Type:
defect
Priority:
Not set
Severity:
normal

Tracking

()

Status:
RESOLVED INVALID

People

(Reporter: kanasimi, Unassigned)

Details

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-TW; rv:1.9.2) Gecko/20100115 Firefox/3.6 (.NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-TW; rv:1.9.2) Gecko/20100115 Firefox/3.6 (.NET CLR 3.5.30729)

When I run a script like this:

var biggest_exponent_of_10=0,test_num=1;
while(parseInt(test_num*=10)-1===test_num-1)
	biggest_exponent_of_10++;
alert(biggest_exponent_of_10);

It gets 308.
The correct number should be 20 in a 32bit computer.


Reproducible: Always

Steps to Reproduce:
1. Create a file:

<html><head></head><body>

<script type="text/javascript">
var biggest_exponent_of_10=0,test_num=1;
while(parseInt(test_num*=10)-1===test_num-1)
	biggest_exponent_of_10++;
alert(biggest_exponent_of_10);
</script>

</body></html>


2. Just run it.

Actual Results:  
It gets 308.



Expected Results:  
The correct number should be 20 in a 32bit computer.
Javascript numbers are double-precision 64-bit format IEEE 754 on all platforms. alert(Number.MAX_VALUE) gives 1.7976931348623157e+308 - so 308 would seem right here.
Status: UNCONFIRMED → RESOLVED
Closed: 14 years ago
Resolution: --- → INVALID
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