如何将两个浮点数填充到其中一个的精度？

Question

I have two numbers, for example:

var a = $('input#number_1').val(); // 12;
var b = $('input#number_2').val(); // 0.01;

How to fill a to precision of b?

a: 12.01
b: 0.01

or fill both to for example:

a: 12.0000
b: 0.0100

Edit:

var a = parseFloat($('input#number_1').val()); // 12;
var b = parseFloat($('input#number_2').val()); // 0.01;

Answer 1

The first thing to realize is that in your code, a and b are strings , not numbers.

What you could do is convert them both to number, the do a simple toString , find out how many digits are after the . in each of them, and then use the larger of those numbers with toFixed on the numbers (which lets you say how many places after the decimal you want).

For example:

 var a = $('input#number_1').val(); var b = $('input#number_2').val(); // Convert them to numbers var aValue = +a; var bValue = +b; // Find out which has more digits after the decimal var maxDigits = 0; var n; a = String(aValue); n = a.indexOf('.'); if (n !== -1) { maxDigits = a.length - n - 1; } b = String(bValue); n = b.indexOf('.'); if (n !== -1) { maxDigits = Math.max(b.length - n - 1, maxDigits); } // Convert back to strings with that many of digits a = aValue.toFixed(maxDigits); b = bValue.toFixed(maxDigits); // Put them back in the fields if that's what you want $('input#number_1').val(a); $('input#number_2').val(b);

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script> <input id="number_1" value="12"> <input id="number_2" value="0.01">

Answer 2

try this javascript toFixed function, which is used for fix decimal value . you can set number of decimal value to function. make sure what you are passing. you may change it as per your requirement,

 var num = 5; var n = num.toFixed(2) alert(n); num = 5.6785; n = num.toFixed(2) alert(n);

Refrence: http://www.w3schools.com/jsref/jsref_tofixed.asp