2 custom functions to retain two decimal places in JavaScript_javascript tips

For some floating-point numbers with multiple digits after the decimal point, we may only need to reserve 2 digits, but js does not provide such a direct function, so we have to write our own function to implement this function. The code is as follows:

Copy code The code is as follows:

function changeTwoDecimal(x) {
var f_x = parseFloat(x);
if (isNaN(f_x)) {
alert('function:changeTwoDecimal->parameter error');
return false;
}
var f_x = Math.round(x * 100 ) / 100;
Return f_x;
}

Function: Round the floating point number to 2 decimal places Usage: changeTwoDecimal(3.1415926) returns 3.14 changeTwoDecimal(3.1475926) returns 3.15

js retains 2 decimal places (mandatory)

For decimal places greater than 2 digits, it is no problem to use the above function, but if it is less than 2 digits, such as: changeTwoDecimal(3.1), it will return 3.1. If you must need a format like 3.10, then you need the following This function:

Copy code The code is as follows:

function changeTwoDecimal_f(x) {
var f_x = parseFloat(x);
if (isNaN(f_x)) {
alert('function:changeTwoDecimal->parameter error');
return false;
}
var f_x = Math.round(x * 100) / 100;
var s_x = f_x.toString();
var pos_decimal = s_x.indexOf('.');
if (pos_decimal < 0) {
pos_decimal = s_x.length;
s_x = '.';
}
while (s_x.length <= pos_decimal 2) {
s_x = '0';
}
        return s_x; String format usage: changeTwoDecimal(3.1415926) returns 3.14 changeTwoDecimal(3.1) returns 3.10