The first, using Math.Round
| The code is as follows |
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var original=28.453
1)//round "original" to two decimals
var result=math.round (original*100)/100; Returns 28.45
2)//Round "original" to 1 decimal
var result=math.round (original*10)/10; Returns 28.5
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The second, js1.5 above can be used tofixed (x), you can specify the number of intercepted decimal point x
| The code is as follows |
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3)//round "original" to two decimals
var result=original.tofixed (2); Returns 28.45 4)//Round "original" to 1 decimal
var result=original.tofixed (1); Returns 28.5 |
The above two methods are most common, but can not meet certain special requirements, such as retaining two digits after the decimal point, if less than two, less than two bit 0. Now there is a third way.
I've sorted out some of these reserved decimal functions
| The code is as follows |
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| Keep two decimal digits
Function: Rounding floating-point numbers, taking 2 digits after the decimal point
function ToDecimal (x) {
var f = parsefloat (x);
if (isNaN (f)) {
Return
}
f = Math.Round (x*100)/100;
return F;
}
The system retains 2 decimal places, such as: 2, will be 00 after 2. That is 2.00
Function ToDecimal2 (x) {
var f = parsefloat (x);
if isNaN (f ) {
return false;
}
& nbsp; var f = math.round (x*100)/100;
var s = f.tostring ();
&nbs p; var rs = s.indexof ('. ');
if (Rs < 0) {
rs = s.length;
S + = '. ';
}
while (s.length <= RS + 2) {
&nbs p; s + = ' 0 ';
}
return s;
}& nbsp. function Fomatfloat (src,pos) {
Return Math.Round (Src*math.pow, POS))/math.pow (POS);
}
Rounded
Alert ("Retain 2 decimal places:" + todecimal (3.14159267));
Alert ("Force retention of 2 decimal places:" + toDecimal2 (3.14159267));
Alert ("Retain 2 decimal places:" + todecimal (3.14559267));
Alert ("Force retention of 2 decimal places:" + toDecimal2 (3.15159267));
Alert ("Retain 2 decimal places:" + fomatfloat (3.14559267, 2));
Alert ("Retain 1 decimal places:" + fomatfloat (3.15159267, 1));
Five homes six into
Alert ("Keep 2 decimal places:" + 1000.003.toFixed (2));
Alert ("Keep 1 decimal places:" + 1000.08.toFixed (1));
Alert ("Keep 1 decimal places:" + 1000.04.toFixed (1));
Alert ("Keep 1 decimal places:" + 1000.05.toFixed (1));
Scientific count
Alert (3.1415.toExponential (2));
Alert (3.1455.toExponential (2));
Alert (3.1445.toExponential (2));
Alert (3.1465.toExponential (2));
Alert (3.1665.toExponential (1));
Accurate to n-bit, excluding n-bit
Alert ("Accurate to decimal point 2nd" + 3.1415.toPrecision (2));
Alert ("Accurate to decimal point 3rd" + 3.1465.toPrecision (3));
Alert ("Accurate to decimal point 2nd" + 3.1415.toPrecision (2));
Alert ("Accurate to decimal point 2nd" + 3.1455.toPrecision (2));
Alert ("Accurate to decimal point 5th" + 3.141592679287.toPrecision (5));
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