javascript trunc() function

javascript bit-manipulation bitwise-operators

As an addition to the @Daniel's answer, if you want to truncate always towards zero, you can:

function truncate(n) {  return n | 0; // bitwise operators convert operands to 32-bit integers}

Or:

function truncate(n) {  return Math[n > 0 ? "floor" : "ceil"](n);}

Both will give you the right results for both, positive and negative numbers:

truncate(-3.25) == -3;truncate(3.25) == 3;

javascript bit-manipulation bitwise-operators

For positive numbers:

Math.floor(2.6) == 2;

For negative numbers:

Math.ceil(-2.6) == -2;

javascript bit-manipulation bitwise-operators

You can use toFixed method that also allows to specify the number of decimal numbers you want to show:

var num1 = new Number(3.141592);var num2 = num1.toFixed(); // 3var num3 = num1.toFixed(2); // 3.14var num4 = num1.toFixed(10); // 3.1415920000

Just note that toFixed rounds the number:

var num1 = new Number(3.641592);var num2 = num1.toFixed(); // 4

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