Tools & Wizards About Us
ivm.vu.nl screenshot

Report Summary

  • 48

    Performance

    Renders faster than
    68% of other websites

  • 85

    Accessibility

    Visual factors better than
    that of 60% of websites

  • 92

    Best Practices

    More advanced features
    available than in
    82% of websites

  • 92

    SEO

    Google-friendlier than
    75% of websites

ivm.vu.nl

Instituut voor Milieuvraagstukken (IVM) - Vrije Universiteit Amsterdam

Page Load Speed

4.6 sec in total

First Response

541 ms

Resources Loaded

3.9 sec

Page Rendered

150 ms

ivm.vu.nl screenshot

About Website

Welcome to ivm.vu.nl homepage info - get ready to check IVM Vu best content for Netherlands right away, or after learning these important things about ivm.vu.nl

Het Instituut voor Milieuvraagstukken (IVM) is een interdisciplinair instituut van de VU en is verbonden aan de Faculteit der Bètawetenschappen.

Visit ivm.vu.nl

Key Findings

We analyzed Ivm.vu.nl page load time and found that the first response time was 541 ms and then it took 4.1 sec to load all DOM resources and completely render a web page. This is a poor result, as 60% of websites can load faster.

Performance Metrics

ivm.vu.nl performance score

48

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value2.2 s

77/100

10%

LCP (Largest Contentful Paint)

Value12.0 s

0/100

25%

SI (Speed Index)

Value9.8 s

10/100

10%

TBT (Total Blocking Time)

Value290 ms

80/100

30%

CLS (Cumulative Layout Shift)

Value0.003

100/100

15%

TTI (Time to Interactive)

Value16.6 s

5/100

10%

Network Requests Diagram

ivm.vu.nl

541 ms

index.aspx

617 ms

static

736 ms

ga.js

5 ms

theme_ivm

422 ms

Our browser made a total of 35 requests to load all elements on the main page. We found that 86% of them (30 requests) were addressed to the original Ivm.vu.nl, 6% (2 requests) were made to Google-analytics.com and 6% (2 requests) were made to Vu.nl. The less responsive or slowest element that took the longest time to load (1.5 sec) belongs to the original domain Ivm.vu.nl.

Page Optimization Overview & Recommendations

Page size can be reduced by 98.0 kB (10%)

Content Size

998.0 kB

After Optimization

900.0 kB

  • HTML
  • Images
  • JavaScript
  • CSS

In fact, the total size of Ivm.vu.nl main page is 998.0 kB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. 25% of websites need less resources to load. Images take 893.0 kB which makes up the majority of the site volume.

HTML Optimization

-82%

Potential reduce by 34.5 kB

  • Original 42.2 kB
  • After minification 31.2 kB
  • After compression 7.7 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 10.9 kB, which is 26% 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 34.5 kB or 82% of the original size.

Image Optimization

-4%

Potential reduce by 31.7 kB

  • Original 893.0 kB
  • After minification 861.3 kB

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. IVM Vu images are well optimized though.

JavaScript Optimization

-49%

Potential reduce by 28.2 kB

  • Original 58.2 kB
  • After minification 57.4 kB
  • After compression 29.9 kB

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 28.2 kB or 49% of the original size.

CSS Optimization

-77%

Potential reduce by 3.6 kB

  • Original 4.7 kB
  • After minification 3.0 kB
  • After compression 1.1 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. Ivm.vu.nl needs all CSS files to be minified and compressed as it can save up to 3.6 kB or 77% of the original size.

Requests Breakdown

Number of requests can be reduced by 16 (50%)

Requests Now

32

After Optimization

16

  • Images
  • JavaScript
  • CSS

The browser has sent 32 CSS, Javascripts, AJAX and image requests in order to completely render the main page of IVM Vu. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 6 to 1 for JavaScripts and as a result speed up the page load time.

Network Requests Diagram

ivm.vu.nl

ivm.vu.nl

541 ms

index.aspx

index.aspx

617 ms

static

static

736 ms

ga.js

ga.js

5 ms

theme_ivm

theme_ivm

422 ms

jquery.cycle.all.min.js

jquery.cycle.all.min.js

452 ms

ga-searchengines.js

ga-searchengines.js

453 ms

ga-links.js

ga-links.js

607 ms

colorbox.css

colorbox.css

233 ms

jquery.colorbox-min.js

jquery.colorbox-min.js

260 ms

body_bg.png

body_bg.png

245 ms

marine-litter-symposium_tcm234-751703.jpg

marine-litter-symposium_tcm234-751703.jpg

254 ms

vulogo-wit-en-banner_tcm234-255716.png

vulogo-wit-en-banner_tcm234-255716.png

288 ms

banner_newvideo_tcm234-218649.jpg

banner_newvideo_tcm234-218649.jpg

456 ms

AWS_banner2_tcm234-755953.jpg

AWS_banner2_tcm234-755953.jpg

467 ms

footer_vua_en_tcm234-14398.gif

footer_vua_en_tcm234-14398.gif

382 ms

defaultsprite.png

defaultsprite.png

564 ms

restyle_intranet_arrow.gif

restyle_intranet_arrow.gif

477 ms

logo_tcm234-70179.png

logo_tcm234-70179.png

550 ms

general_menu_separator.gif

general_menu_separator.gif

631 ms

Environmental-Economics_tcm234-751981.jpg

Environmental-Economics_tcm234-751981.jpg

1131 ms

arrow2.gif

arrow2.gif

689 ms

accordion_down_1.png

accordion_down_1.png

691 ms

accordion_down_2.png

accordion_down_2.png

783 ms

accordion_down_3.png

accordion_down_3.png

778 ms

Zd2E9abXLFGSr9G3YK2MsFzqCfRpIA3W6ypxnPISCPA.woff

Zd2E9abXLFGSr9G3YK2MsFzqCfRpIA3W6ypxnPISCPA.woff

69 ms

__utm.gif

__utm.gif

48 ms

border3.png

border3.png

796 ms

border4.png

border4.png

867 ms

loading.gif

loading.gif

858 ms

cookie-bar-bg.png

cookie-bar-bg.png

937 ms

epa_tcm234-751983.jpg

epa_tcm234-751983.jpg

1298 ms

Spatial_groot_tcm234-751984.jpg

Spatial_groot_tcm234-751984.jpg

1495 ms

Teaching-Program_tcm234-751985.jpg

Teaching-Program_tcm234-751985.jpg

1347 ms

print.css

print.css

235 ms

Accessibility Review

ivm.vu.nl accessibility score

85

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-*] attributes do not match their roles

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

Image elements do not have [alt] attributes

Best Practices

ivm.vu.nl 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

ivm.vu.nl SEO score

92

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

Image elements do not have [alt] attributes

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

Language and Encoding

  • Language Detected

    NL

  • Language Claimed

    EN

  • Encoding

    UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Ivm.vu.nl can be misinterpreted by Google and other search engines. Our service has detected that Dutch is used on the page, and it does not match the claimed English language. Our system also found out that Ivm.vu.nl 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

ivm.vu.nl

Open Graph description is not detected on the main page of IVM Vu. Lack of Open Graph description can be counter-productive for their social media presence, as such a description allows converting a website homepage (or other pages) into good-looking, rich and well-structured posts, when it is being shared on Facebook and other social media. For example, adding the following code snippet into HTML <head> tag will help to represent this web page correctly in social networks: