JavaScript Study Notes (4) Number Number Type_Basic Knowledge

toFixed() method specifies the number of decimal places
toExponential() method uses scientific notation to express the number, and the parameter specifies the number of decimal places
toPrecision() method automatically determines whether to call the toFixed() or toExponential() method, and the parameter specifies The number of digits in all numbers

Copy code The code is as follows:

var num = 99;
alert(toFixed(2)); //99.00
alert(toExponential(1)); //9.0e 1
alert(toPrecision(1)); //9.0e 1
alert(toPrecision (2)); //99
alert(toPrecision(3)); //99.0