复选框用于切换状态，因此我们绑定到 input.checked 而非 input.value：
App.svelte
<input type="checkbox" bind:checked={yes}>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
<script>
let yes = false;
</script>
<label>
<input type="checkbox" checked={yes} />Yes! Send me regular email spam
</label>
{#if yes}<p>
Thank you. We will bombard your inbox and sell
your personal details.
</p>
{:else}<p>
You must opt in to continue. If you're not
paying, you're the product.
</p>
{/if}<button disabled={!yes}>Subscribe</button>