Wednesday, October 13, 2010

How to round numbers in JavaScript?

You can use Math Object or Bitwise Operator for round a number:

round(a) - Returns the value of a to the nearest integer. If the values decimal value is .5 or greater the next highest integer value is returned otherwise the next lowest integer is returned.


floor(a) - Rounds the passed value down to the previous integer. If the passed value is already an integer the returned value is the same as the passed value.


ceil(x) - Rounds up the value of "a" to the next integer. If the value is a already whole number, the return value will be the same as the passed value.

<script type="text/javascript">
var original=28.453;
//round "original" to the nearest integer
var result = Math.round(original);  //returns 28
//other way
var result = original >> 0;  //returns 28

//round "original" to  down to the previous integer
var result = Math.floor(original);  //returns 28
//round "original" to  up to the next integer
var result = Math.ceil(original);  //returns 29

//round "original" to two decimals
var result = Math.round(original*100)/100;  //returns 28.45
// other way
var result = (original *100 >> 0) *0.01;  //returns 28.45
</script>

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