当前位置：文江博客知识库 en-US 文档 Web API CSSPrimitiveValue getFloatValue

CSSPrimitiveValue.getFloatValue() - Web APIs 编辑

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.

Syntax

var floatValue = cssPrimitiveValue.getFloatValue(unit);

Parameters

unitType

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.

Example

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

Specifications

Specification	Status	Comment
Document Object Model (DOM) Level 2 Style Specification The definition of 'CSSPrimitiveValue.getFloatValue' in that specification.	Obsolete	Initial definition