CSSPrimitiveValue: getFloatValue() method

The getFloatValue() method of the CSSPrimitiveValue interface is used to get a float value in a specified unit. If this CSS value doesn’t contain a float value or can’t be converted into the specified unit, a DOMException is raised.

[!NOTE] This method was part of an attempt to create a typed CSS Object Model. This attempt has been abandoned, and most browsers do not implement it.

To achieve your purpose, you can use:

• the untyped CSS Object Model, widely supported, or
• the modern CSS Typed Object Model API, less supported and considered experimental.

Syntax

getFloatValue(unit)

Parameters

• unit

  • : An unsigned short representing the code for the unit type, in which the value should be returned. Valid values are:

    Constant	Description
    CSS_CM	The value is a <length> in centimeters.
    CSS_DEG	The value is an <angle> in degrees.
    CSS_DIMENSION	The value is a <number> with an unknown dimension.
    CSS_EMS	The value is a <length> in em units.
    CSS_EXS	The value is a <length> in ex units.
    CSS_GRAD	The value is an <angle> in grads.
    CSS_HZ	The value is a <frequency> in Hertz. The value can be obtained by using the getFloatValue method.
    CSS_IN	The value is a <length> in inches.
    CSS_KHZ	The value is a <frequency> in Kilohertz.
    CSS_MM	The value is a <length> in millimeters.
    CSS_MS	The value is a <time> in milliseconds.
    CSS_NUMBER	The value is a simple <number>.
    CSS_PC	The value is a <length> in picas.
    CSS_PERCENTAGE	The value is a <percentage>.
    CSS_PT	The value is a <length> in points.
    CSS_PX	The value is a <length> in pixels.
    CSS_RAD	The value is an <angle> in radians.
    CSS_S	The value is a <time> in seconds.

Return value

A float value in the specified unit.

Exceptions

Type	Description
DOMException	An INVALID_ACCESS_ERR is raised if the CSS value doesn't contain a float value or if the float value can't be converted into the specified unit.

Examples

const cs = window.getComputedStyle(document.body);
const cssValue = cs.getPropertyCSSValue("margin-top");
console.log(cssValue.getFloatValue(CSSPrimitiveValue.CSS_CM));

Specifications

This feature was originally defined in the DOM Style Level 2 specification, but has been dropped from any standardization effort since then.

It has been superseded by a modern, but incompatible, CSS Typed Object Model API that is now on the standard track.

Browser compatibility