This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The newValueSpecifiedUnits() method of the SVGLength interface resets the value as a number with an associated unitType, thereby replacing the values for all of the attributes on the object.
newValueSpecifiedUnits(unitType, valueInSpecifiedUnits)
unitTypeA constant representing the unit type to which the length's value should be converted. This must be one of the constant values defined for the unitType property, with the exception of SVG_LENGTHTYPE_UNKNOWN.
SVGLength.SVG_LENGTHTYPE_NUMBER: convert to unitless numberSVGLength.SVG_LENGTHTYPE_PERCENTAGE: convert to percentageSVGLength.SVG_LENGTHTYPE_EMS: convert to em unitsSVGLength.SVG_LENGTHTYPE_EXS: convert to ex unitsSVGLength.SVG_LENGTHTYPE_PX: convert to pixelsSVGLength.SVG_LENGTHTYPE_CM: convert to centimetersSVGLength.SVG_LENGTHTYPE_MM: convert to millimetersSVGLength.SVG_LENGTHTYPE_IN: convert to inchesSVGLength.SVG_LENGTHTYPE_PT: convert to pointsSVGLength.SVG_LENGTHTYPE_PC: convert to picasvalueInSpecifiedUnitsThe numeric factor for the length value, expressed in the specified unit type.
None (undefined).
This method may raise a DOMException of one of the following types:
NotSupportedError DOMException
Thrown if unitType is SVG_LENGTHTYPE_UNKNOWN or not a valid unit type constant.
NoModificationAllowedError DOMException
Thrown if SVGLength corresponds to a read-only attribute or when the object itself is read-only.
// Get an SVGLength object
const svg = document.querySelector("svg");
const length = svg.createSVGLength();
// Set a new value with specific units
length.newValueSpecifiedUnits(SVGLength.SVG_LENGTHTYPE_NUMBER, 45);
console.log(length.valueInSpecifiedUnits); // Output: 45
console.log(length.unitType); // Output: 1 (SVG_LENGTHTYPE_NUMBER)
console.log(length.value); // The value converted to the user coordinate system
// Change the value to pixels
length.newValueSpecifiedUnits(SVGLength.SVG_LENGTHTYPE_PX, 100);
console.log(length.valueInSpecifiedUnits); // Output: 100
console.log(length.unitType); // Output: 5 (SVG_LENGTHTYPE_PX)
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | WebView on iOS | |
newValueSpecifiedUnits |
1 | 12 | 1.5 | ≤12.1 | 3 | 18 | 4 | ≤12.1 | 1 | 1.0 | 4.4 | 1 |
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https://developer.mozilla.org/en-US/docs/Web/API/SVGLength/newValueSpecifiedUnits