How can I set multiple CSS styles in JavaScript?

Question

I have the following JavaScript variables:

var fontsize = "12px"
var left= "200px"
var top= "100px"

I know that I can set them to my element iteratively like this:

document.getElementById("myElement").style.top=top
document.getElementById("myElement").style.left=left

Is it possible to set them all together at once, something like this?

document.getElementById("myElement").style = allMyStyle 

Answer 1

If you have the CSS values as string and there is no other CSS already set for the element (or you don't care about overwriting), make use of the cssText property:

document.getElementById("myElement").style.cssText = "display: block; position: absolute";

You can also use template literals for an easier, more readable multiline CSS-like syntax:

document.getElementById("myElement").style.cssText = `
  display: block; 
  position: absolute;
`;

This is good in a sense as it avoids repainting the element every time you change a property (you change them all "at once" somehow).

On the other side, you would have to build the string first.