Tools & Wizards About Us
cstl.org screenshot

Report Summary

  • 32

    Performance

    Renders faster than
    52% of other websites

  • 82

    Accessibility

    Visual factors better than
    that of 52% of websites

  • 92

    Best Practices

    More advanced features
    available than in
    80% of websites

  • 83

    SEO

    Google-friendlier than
    46% of websites

cstl.org

Center for Science Teaching & Learning | Class in Tanglewood

Page Load Speed

8.2 sec in total

First Response

35 ms

Resources Loaded

7.4 sec

Page Rendered

684 ms

cstl.org screenshot

About Website

Click here to check amazing Cstl content for United States. Otherwise, check out these important facts you probably never knew about cstl.org

Center for Science Teaching & Learning at Tanglewood Preserve In Rockville Centre, NY offers science classes, educational workshops and more. Book online now!

Visit cstl.org

Key Findings

We analyzed Cstl.org page load time and found that the first response time was 35 ms and then it took 8.1 sec to load all DOM resources and completely render a web page. This is a poor result, as 85% of websites can load faster.

Performance Metrics

cstl.org performance score

32

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value3.1 s

47/100

10%

LCP (Largest Contentful Paint)

Value4.6 s

34/100

25%

SI (Speed Index)

Value6.2 s

43/100

10%

TBT (Total Blocking Time)

Value1,530 ms

13/100

30%

CLS (Cumulative Layout Shift)

Value0.174

69/100

15%

TTI (Time to Interactive)

Value21.7 s

1/100

10%

Network Requests Diagram

cstl.org

35 ms

cstl.org

583 ms

145 ms

jquery.min.js

24 ms

56 ms

Our browser made a total of 34 requests to load all elements on the main page. We found that 35% of them (12 requests) were addressed to the original Cstl.org, 18% (6 requests) were made to Youtube.com and 12% (4 requests) were made to Dipr2nuwo661l.cloudfront.net. The less responsive or slowest element that took the longest time to load (6.6 sec) belongs to the original domain Cstl.org.

Page Optimization Overview & Recommendations

Page size can be reduced by 1.6 MB (42%)

Content Size

3.9 MB

After Optimization

2.3 MB

  • HTML
  • Images
  • JavaScript
  • CSS

In fact, the total size of Cstl.org main page is 3.9 MB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. Only a small number of websites need less resources to load. Images take 2.3 MB which makes up the majority of the site volume.

HTML Optimization

-85%

Potential reduce by 156.6 kB

  • Original 184.6 kB
  • After minification 156.6 kB
  • After compression 28.0 kB

HTML content can be minified and compressed by a website’s server. The most efficient way is to compress content using GZIP which reduces data amount travelling through the network between server and browser. This page needs HTML code to be minified as it can gain 28.0 kB, which is 15% of the original size. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 156.6 kB or 85% of the original size.

Image Optimization

-52%

Potential reduce by 1.2 MB

  • Original 2.3 MB
  • After minification 1.1 MB

Image size optimization can help to speed up a website loading time. The chart above shows the difference between the size before and after optimization. Obviously, Cstl needs image optimization as it can save up to 1.2 MB or 52% of the original volume. The most popular and efficient tools for JPEG and PNG image optimization are Jpegoptim and PNG Crush.

JavaScript Optimization

-20%

Potential reduce by 261.6 kB

  • Original 1.3 MB
  • After minification 1.3 MB
  • After compression 1.0 MB

It’s better to minify JavaScript in order to improve website performance. The diagram shows the current total size of all JavaScript files against the prospective JavaScript size after its minification and compression. It is highly recommended that all JavaScript files should be compressed and minified as it can save up to 261.6 kB or 20% of the original size.

CSS Optimization

-3%

Potential reduce by 2.8 kB

  • Original 93.5 kB
  • After minification 93.5 kB
  • After compression 90.7 kB

CSS files minification is very important to reduce a web page rendering time. The faster CSS files can load, the earlier a page can be rendered. Cstl.org has all CSS files already compressed.

Requests Breakdown

Number of requests can be reduced by 14 (47%)

Requests Now

30

After Optimization

16

  • AJAX
  • Images
  • JavaScript
  • CSS

The browser has sent 30 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Cstl. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 12 to 1 for JavaScripts and from 4 to 1 for CSS and as a result speed up the page load time.

Network Requests Diagram

cstl.org

cstl.org

35 ms

cstl.org

cstl.org

583 ms

145 ms

jquery.min.js

jquery.min.js

24 ms

56 ms

cropped-CSTL-logo1-1.png

cropped-CSTL-logo1-1.png

58 ms

7PhevZqKM_k

7PhevZqKM_k

121 ms

backgroun_cstl_720.jpg

backgroun_cstl_720.jpg

90 ms

sbi-sprite.png

sbi-sprite.png

38 ms

sf2024_2.png

sf2024_2.png

6611 ms

sunday-science-button4.png

sunday-science-button4.png

609 ms

slide-11-3.png

slide-11-3.png

365 ms

www-player.css

www-player.css

7 ms

www-embed-player.js

www-embed-player.js

25 ms

base.js

base.js

48 ms

integration-kit-bundle.js

integration-kit-bundle.js

276 ms

ad_status.js

ad_status.js

402 ms

UCY5Klx_0fJhMytIltuKLUwnjJON9GWedkq6jjIrpW0.js

UCY5Klx_0fJhMytIltuKLUwnjJON9GWedkq6jjIrpW0.js

442 ms

embed.js

embed.js

306 ms

475 ms

KFOlCnqEu92Fr1MmEU9fBBc9.ttf

KFOlCnqEu92Fr1MmEU9fBBc9.ttf

336 ms

KFOmCnqEu92Fr1Mu4mxP.ttf

KFOmCnqEu92Fr1Mu4mxP.ttf

339 ms

style-cart.a02642c318da0638f31a.css

style-cart.a02642c318da0638f31a.css

215 ms

fonts.eacdf4961de415ddab83.css

fonts.eacdf4961de415ddab83.css

329 ms

id

id

106 ms

dinasour-bkgd-1.png

dinasour-bkgd-1.png

636 ms

Create

Create

138 ms

output.29011c62dc48.js

output.29011c62dc48.js

128 ms

js

js

166 ms

djangojs.js

djangojs.js

117 ms

output.48e667744f3a.js

output.48e667744f3a.js

125 ms

GenerateIT

GenerateIT

39 ms

20231021_203618-rotated.jpg

20231021_203618-rotated.jpg

125 ms

log_event

log_event

22 ms

Accessibility Review

cstl.org accessibility score

82

Accessibility Issues

ARIA

These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.

Impact

Issue

High

[aria-hidden="true"] elements contain focusable descendents

High

ARIA IDs are not unique

Contrast

These are opportunities to improve the legibility of your content.

Impact

Issue

High

Background and foreground colors do not have a sufficient contrast ratio.

Names and labels

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Impact

Issue

High

Links do not have a discernible name

Tables and lists

These are opportunities to improve the experience of reading tabular or list data using assistive technology, like a screen reader.

Impact

Issue

High

Lists do not contain only <li> elements and script supporting elements (<script> and <template>).

Best Practices

cstl.org best practices score

92

Areas of Improvement

Trust and Safety

Impact

Issue

High

Does not use HTTPS

Low

Ensure CSP is effective against XSS attacks

General

Impact

Issue

Low

Detected JavaScript libraries

High

Missing source maps for large first-party JavaScript

SEO Factors

cstl.org SEO score

83

Search Engine Optimization Advices

Content Best Practices

Format your HTML in a way that enables crawlers to better understand your app’s content.

Impact

Issue

High

Links do not have descriptive text

Crawling and Indexing

To appear in search results, crawlers need access to your app.

Impact

Issue

High

Links are not crawlable

Mobile Friendly

Make sure your pages are mobile friendly so users don’t have to pinch or zoom in order to read the content pages. [Learn more](https://developers.google.com/search/mobile-sites/).

Impact

Issue

High

Document uses legible font sizes

High

Tap targets are not sized appropriately

Language and Encoding

  • Language Detected

    EN

  • Language Claimed

    EN

  • Encoding

    UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Cstl.org can be misinterpreted by Google and other search engines. Our service has detected that English is used on the page, and it matches the claimed language. Our system also found out that Cstl.org main page’s claimed encoding is utf-8. Use of this encoding format is the best practice as the main page visitors from all over the world won’t have any issues with symbol transcription.

Social Sharing Optimization

cstl.org

Open Graph data is detected on the main page of Cstl. This is the best way to make the web page social media friendly. Here is how it looks like on Facebook: