Someone asked a JS question:
Copy Code code as follows:
var i = 0.07;
var r = i*100;
Alert (R);
The result is 7.0000000000000001?
Check the data, in fact, we know that in Javsscript, variables are stored without distinguishing between number and float types, but uniformly by float storage. and JavaScript stores number in 64bit floating-point format defined by the IEEE 754-2008 standard, as defined by IEEE 754: http://en.wikipedia.org/wiki/IEEE_754-2008
Decimal64 the corresponding section length is 10, the decimal part length is 16, so the default result is "7.0000000000000001", if the last decimal is 0, then 1 is used as a valid digit mark.
Similarly, we can imagine that the 1/3 result should be 0.3333333333333333.
So how do you correct this value?
You can use the following methods:
First, parseint
var r4=parseint (i*100);
Second, Math.Round
var r2=math.round ((i*100) *1000)/1000;
Both of the above methods can be 7
Attach all test code:
Copy Code code as follows:
<title> Test Scripts </title>
<script language= "JAVASCRIPT" >
function init ()
{
var i = 0.07;
var r = i*100;
var r2=math.round ((i*100) *1000)/1000;
var r3 = eval (i*100);
var r4=parseint (i*100);
var r5=parsefloat (i*100*1.0000);
var r6= (1/3);
Alert (R);
Alert ("math.round=" +R2);
Alert ("eval=" +R3);
Alert ("parseint=" +R4);
Alert ("parsefloat=" +R5);
Alert ("" +R6);
}
</script>
<body onload= "Init ();" >
</body>
