ui.html

<h2>Rectangle Creator</h2>
<p>Count: <input id="count" value="5"></p>
<button id="create">Create</button>
<button id="cancel">Cancel</button>
<script>
    document.getElementById('create').onclick = () => {
        const textbox = document.getElementById('count');
        const count = parseInt(textbox.value, 10);
        // 传递 json 数据
        parent.postMessage({
            pluginMessage: {
                type: 'create-rectangles',
                count
            }
        }, '*')
    }

    document.getElementById('cancel').onclick = () => {
        parent.postMessage({
            pluginMessage: {
                type: 'cancel'
            }
        }, '*')
    }
</script>