March 17, 2000 - IE5.5's Number Formatting

Yehuda Shiran March 17, 2000
IE5.5's Number Formatting
Tips: March 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.

    Exprience some of these functions by yourself in Column 59, IE 5.5: Formatting, URIs, and Stack Operations.