May 5, 2000 - Formatting Numbers

Yehuda Shiran May 5, 2000
Formatting Numbers
Tips: May 2000

Yehuda Shiran, Ph.D.
Doc JavaScript

Until IE5.5, formatting numbers was a real challenge. We all used high mathematical functions such as Math.ceil and Math.pow to format numbers the way we wanted to. IE5.5 fixes this problem with three new methods of the Number prototype object:

toFixed(fractionDigits) 
toExponential(fractionDigits) 
toPrecision(precision)

The toFixed(fractionDigits) method formats a number with fractionDigits digits after the decimal place. Suppose:

x = 1234.56789

and you call alert(x.toFixed(4)), you'll get 1234.5679 in IE5.5.

The toExponential(fractionDigits) method formats a number with fractionDigits digits after the decimal place, in exponential notation. Suppose:

x = 1234.56789

and you call alert(x.toExponential(2)), you'll get 1.23e+3 in IE5.5.

The toPrecision(precision) method formats a number with total precision number of digits, in exponential notation if needed. Suppose:

x = 1234.56789

and you call alert(x.toPrecision(2)), you'll get 1.2e+3 in IE5.5.

When you call alert(x.toPrecision(9)), you'll get 1234.56789 in IE5.5