svelte/documentation/tutorial/06-bindings/11-dimensions/text.md

title
Dimensions

Every block-level element has clientWidth, clientHeight, offsetWidth and offsetHeight bindings:

<div bind:clientWidth={w} bind:clientHeight={h}>
	<span style="font-size: {size}px">{text}</span>
</div>

These bindings are readonly — changing the values of w and h won't have any effect.

Elements are measured using a technique similar to this one. There is some overhead involved, so it's not recommended to use this for large numbers of elements.

display: inline elements cannot be measured with this approach; nor can elements that can't contain other elements (such as <canvas>). In these cases you will need to measure a wrapper element instead.