Javascript numbers keep digits after decimal point

We can see that many people want to retain the decimal point after the number, but most of them write a function to intercept the number, and consider rounding it down. It is quite complicated to write it.

In fact, the javascript Number object has a method to retain decimal places: toFixed, which is the Number after rounding.

I was worried that IE6 did not support this method at one time. As shown in MDN, this method was implemented only by javascript1.5. I tried it in IE6 and it is fully supported.

ToExponential ([fractionDigits]): returns the number in scientific notation, the number of digits retained after the decimal point in the fractionDigits value.

ToFixed ([fractionDigits]): returns the number based on the specified number of decimal places. The fractionDigits value is the number of digits that are retained after the decimal point.

ToPrecision ([precision]): returns a number based on the specified precision (this precision is not the number after the decimal point), where precision is the specified precision value.

Example:

The Code is as follows:

Var n = 12345.6789;

N. toFixed (); // Returns 12346

N. toFixed (1); // Returns 12345.7

N. toFixed (6); // Returns 12345.678900

(1.23e + 20). toFixed (2); // Returns 123000000000000000000.00

(1.23e-10). toFixed (2); // Returns 0.00

2.34.toFixed (1); // Returns 2.3

-2.34.toFixed (1); // Returns-2.3

(-2.24). toFixed (1); // Returns-2.2

Conversion function. This code is from a foreign forum.

The Code is as follows:

Function roundNumber (number, decimals ){

Var newString; // The new rounded number

Decimals = Number (decimals );

If (decimals <1 ){

NewString = (Math. round (number). toString ();

} Else {

Var numString = number. toString ();

If (numString. lastIndexOf (".") =-1) {// If there is no decimal point

NumString + = "."; // give it one at the end

}

Var cutoff = numString. lastIndexOf (".") + decimals; // The point at which to truncate the number

Var d1 = Number (numString. substring (cutoff, cutoff + 1); // The value of the last decimal place that we'll end up

Var d2 = Number (numString. substring (cutoff + 1, cutoff + 2); // The next decimal, after the last one we want

If (d2> = 5) {// Do we need to round up at all? If not, the string will just be truncated

If (d1 = 9 & cutoff> 0) {// If the last digit is 9, find a new cutoff point

While (cutoff> 0 & (d1 = 9 | isNaN (d1 ))){

If (d1! = "."){

Cutoff-= 1;

D1 = Number (numString. substring (cutoff, cutoff + 1 ));

} Else {

Cutoff-= 1;

}

}

}

D1 + = 1;

}

If (d1 = 10 ){

NumString = numString. substring (0, numString. lastIndexOf ("."));

Var roundedNum = Number (numString) + 1;

NewString = roundedNum. toString () + '.';

} Else {

NewString = numString. substring (0, cutoff) + d1.toString ();

}

}

If (newString. lastIndexOf (".") =-1) {// Do this again, to the new string

NewString + = ".";

}

Var decs = (newString. substring (newString. lastIndexOf (".") + 1). length;

For (var I = 0; I

// Var newNumber = Number (newString); // make it a number if you like

Document. roundform. roundedfield. value = newString; // Output the result to the form field (change for your purposes)

}