k</span>(<span class="hljs-params"></span>) {
    <span class="hljs-variable language_">this</span>.<span class="hljs-property">innerHTML</span> = <span class="hljs-string">`&lt;h1&gt;Hello, World!&lt;/h1&gt;`</span>;
  }
}
customElements.<span class="hljs-title function_">define</span>(<span class="hljs-string">&#x27;hello-world&#x27;</span>, <span class="hljs-title class_">HelloWorld</span>);</code></pre><h2 id="8-performance-metrics-amp-core-web-vitals"><a href="#8-performance-metrics-amp-core-web-vitals