类型“ HTMLElement”上不存在属性“ width”

Question

The following TypeScript fails to compile:

let svg = document.createElement("svg");
svg.width = 300;

Due to the error Property 'width' does not exist on type 'HTMLElement' . But if I change svg to canvas , for example, then it does compile, so it's something about SVGs specifically it seems...

Any ideas?

Answer 1

let svg = document.createElement("svg"); doesn't create svg element, but custom html element.

Proper way to create svg element:

let svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");

 const customSvg = document.createElement("svg") const properSvg = document.createElementNS("http://www.w3.org/2000/svg", "svg") console.log(customSvg instanceof SVGSVGElement) // false console.log(properSvg instanceof SVGSVGElement) // true console.log(customSvg.width) // undefined console.log(properSvg.width) // SVGAnimatedLength {} 

Answer 2

As Marzelin explained , the proper way to create an svg element is by using document.createElementNS instead:

document.createElementNS("http://www.w3.org/2000/svg", "svg");

• Related question: Create SVG tag with JavaScript

The TypeScript standard lib knows this well, hence why you are getting a HTMLElement return type inference from document.createElement("svg") instead of SVGSVGElement .

Answer 3

In SVG width and height of elements are attributes and not CSS properties so you'd need to write

 document.getElementById('cercle1').setAttribute("height", "10px"); 

similarly for the width.

Change height/width of object SVG javascript

In your case:

svg.setAttribute("width", "300px");

Answer 4

Your question title is question "Property 'width' does not exist on type 'HTMLElement'"

HTMLElement has no property width it has property style . and style had width

let svg = document.createElement("svg");
svg.style.width = '30px';

In your case you need an SVGSVGElement

var svgEl = document.createElementNS("http://www.w3.org/2000/svg", "svg")
svgEl.width = 300