Is there a dynamic size in HTML5 svg shaping

Question

I am new to HTML.
In the html-basic course there was the following example
<svg width="2000" height="2000">
<rect width="300" height="100"
x="20" y="20" fill="green" />
</svg>
since svg is made to be scalable, can I also use a dynamic size like 5%?
Can I use a previous created variable as factor?
Does the svg shaping only works with whole numbers or would width="0.5" also be possible?

Answer 1

Quick presentation: https://www.w3schools.com/html/html5_svg.asp
Long tutorial: https://www.w3schools.com/graphics/svg_intro.asp

Deep referrence: https://developer.mozilla.org/en-US/docs/Web/SVG

Answer 2

Thanks, I will check it out as soon as I got some more time