How to simulate a bad First Input Delay (Web Core Vitals) score?

By -

I need to create a webpage that will generate a bad First Input Delay (FID) value.

In case you aren't aware, FID is part of Google's Web Core Vitals.

I want to simulate a bad FID because I am testing a website scanning tool that is supposed to flag a bad FID value. Therefore I want to simulate a bad value on a webpage to make sure it works.

To be clear - I am NOT trying to fix my First Input Delay. I want to create a webpage that gives a bad First Input Delay value on purpose.

But I'm not sure how to do that.

I have a HTML page with <button id="button">Click Me</button>. And in the <head> I have added this script:

<script type="module">
// Get the First Input Delay (FID) Score 
import {onFID} from 'https://unpkg.com/web-vitals@3/dist/web-vitals.attribution.js?module';

// Get the button element
const button = document.getElementById('button');

// Add a click event listener to the button
button.addEventListener('click', async () => {
  // Make a delay
  await new Promise((resolve) => setTimeout(resolve, 5000));
  // Print the FID score to the console
  onFID(console.log);
});
</script>

The imported onFID method is what Google uses from Web Vitals to report the FID value.

You can see a live version of the above script here: http://seosins.com/extra-pages/first-input-delay/

But when I click the button, 5000 milliseconds later it only prints a FID of about 3 milliseconds.

The 5000 millisecond delay is not included in the FID value.

Why doesn't it report the FID value as 5003 milliseconds?

When I try to simulate a bad FID value I am doing something wrong.

What could it be?

Update:

As suggested in the comments, I have also tried adding a delay on the server using a Cloudflare Worker. That worker delayed the server response by 5000 milliseconds. But it didn't work, because the FID value was unchanged.

Also I do not think this is the correct approach because FID measures the time from when a user first interacts with your site (i.e. when they click a link, tap on a button, etc) to the time when the browser is actually able to respond to that interaction. While the Cloudflare Worker was only slowing down the initial server response. Therefore I have since removed this experiment from the page.



Comments

Post a Comment

Popular posts from this blog

Today Walkin 14th-Sept

By -
Image
14th Sept 2017 ( GO Through all List) Read Walkin details properly , Try to call company before attending if possible !!! ==================================== 1. Myntra through fresherworld (Call Based , Venue shared to shortlisted candidates) _____________________________ 2. Magna : Hiring for Client Harman : C++
Read more

Spring Elasticsearch Operations

By -
Elasticsearch Operations Spring Data Elasticsearch uses two interfaces to define the operations that can be called against an Elasticsearch index. These are ElasticsearchOperations and ReactiveElasticsearchOperations. Whereas the first is used with the classic synchronous implementations, the second one uses reactive infrastructure. The default implementations of the interfaces offer: Read/Write mapping support for domain types. A rich query and criteria api. Resource management and Exception translation. ElasticsearchTemplate The ElasticsearchTemplate is an implementation of the ElasticsearchOperations interface using the Transport Client. @Configuration public class TransportClientConfig extends ElasticsearchConfigurationSupport {   @Bean   public Client elasticsearchClient() throws UnknownHostException {                      Settings settings = Settings.builder().put("cluster.name", "elasticsearch")....
Read more

Hibernate Search - Elasticsearch with JSON manipulation

By -
Elasticsearch with JSON manipulation Elasticsearch ships with many features. It is possible that at some point, one feature you need will not be exposed by the Search DSL. To work around such limitations, Hibernate Search provides ways to: Transform the HTTP request sent to Elasticsearch for search queries. Read the raw JSON of the HTTP response received from Elasticsearch for search queries. Direct changes to the HTTP request may conflict with Hibernate Search features and be supported differently by different versions of Elasticsearch. Similarly, the content of the HTTP response may change depending on the version of Elasticsearch, depending on which Hibernate Search features are used, and even depending on how Hibernate Search features are implemented. Thus, features relying on direct access to HTTP requests or responses cannot be guaranteed to continue to work when upgrading Hibernate Search, even for micro upgrades (x.y.z to x.y.(z+1)). Use this at your own risk....
Read more