svelte:Read-only bindings

offsetWidth, offsetHeight, clientWidth, clientHeight can be bound, read only, on any block level HTML element, excluding void tags (like br) and elements that are set to be inline (display: inline).

Get a reference to the HTML element in JavaScript

bind:this is a special kind of binding that allows you to get a reference to an HTML element and bind it to a JavaScript variable:

<script>
let myInputField
</script>

<input bind:this={myInputField} />

This is handy when you need to apply logic to elements after you mount them, for example, using the onMount() lifecycle event callback.

Binding components props

Using bind: you can bind a value to any prop that a component exposes.

Say you have a Car.svelte component:

<script>
export let inMovement = false
</script>

<button on:click={() => inMovement = true }>Start car</button>

You can import the component and bind the inMovement prop:

<script>
  import Car from './Car.svelte';

  let carInMovement;
</script>

<Car bind:inMovement={carInMovement} />

{carInMovement}

This can allow for interesting scenarios.