Analyze Professional Development from the Gilder Lehrman Institute of American History

Page load speed analysis

  • 63/100

    Normal result
  • 5

    Successful tests
  • 3

    Failed tests
  • First response

    516 ms

  • Resources loaded

    1.9 sec

  • Page rendered

    561 ms

  • Total page load time

    3 sec

Welcome to homepage info - get ready to check Professional Development Gilder Lehrman best content for United States right away, or after learning these important things about

We analyzed page load time and found that the first response time was 516 ms and then it took 2.5 sec to load all DOM resources and completely render a web page. This is quite a good result, as only 45% of websites can load faster.

Page optimization

  • HTML 31.5 kB
    Images 460.7 kB
    Javascripts 1.6 MB
    CSS 420.8 kB

    In fact, the total size of main page is 2.5 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. 60% of websites need less resources to load. Javascripts take 1.6 MB which makes up the majority of the site volume.

    • Original 31.5 kB
    • After minification 31.4 kB
    • After compression 10.5 kB

    HTML optimization

    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. HTML code on this page is well minified. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 21.1 kB or 67% of the original size.

    • Original 460.7 kB
    • After optimization 456.4 kB

    Image optimization

    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. Professional Development Gilder Lehrman images are well optimized though.

    • Original 1.6 MB
    • After minification 1.1 MB
    • After compression 329.1 kB

    JavaScript optimization

    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 1.2 MB or 79% of the original size.

    • Original 420.8 kB
    • After minification 416.1 kB
    • After compression 64.6 kB

    CSS optimization

    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. needs all CSS files to be minified and compressed as it can save up to 356.3 kB or 85% of the original size.

Network requests diagram

  • jquery.min.js
  • bootstrap.min.js
  • css_e8ab1fe0da2b464b3fa60bab367b972a.css
  • css_d74aeaa7e6b1f5c3ca8434ea791d3514.css
  • jquery-1.6.4.min.js
  • drupal.js
  • fb.js
  • ui.core.min.js
  • ui.datepicker.min.js
  • flowplayer-3.2.6.min.js
  • gli_mweb.js
  • gli_resource_list.js
  • UTIL.js
  • nkbase.js
  • nkbase_favorites.js
  • nkbase_header_image.js
  • og.js
  • panels.js
  • uc_roles.js
  • uc_varprice_show_arb.js
  • dropdown.js
  • GLI.js
  • css
  • gli_logo.png
  • millergli.kd0hlkhp.html
  • all.js
  • analytics.js
  • tlthcollage.jpg
  • united.jpg
  • gTHiwyxi6S7iiHpqAoiE3HhCUOGz7vYGh680lGh-uXM.woff
  • -g5pDUSRgvxvOl5u-a_WHw.woff
  • 114784436
  • collect
  • player.js
  • player.css
  • ga.js
  • vuid.min.js
  • __utm.gif
  • proxy.html
  • 500717833.webp
  • xd_arbiter.php
  • xd_arbiter.php
  • embed.js
  • mapbox.css
  • embed.css
  • features.json
  • 6.png
  • icons-000000@2x.png
  • 5.png
  • 6.png
  • 6.png
  • 7.png
  • 5.png
  • 5.png
  • 7.png
  • 7.png
  • 5.png
  • 5.png
  • 7.png
  • 7.png
  • 6.png
  • 6.png
  • pin-m-library+3887be.png
  • pin-m-library+1087bf.png
  • nr-885.min.js

Our browser made a total of 67 requests to load all elements on the main page. We found that 36% of them (24 requests) were addressed to the original, 24% (16 requests) were made to and 10% (7 requests) were made to The less responsive or slowest element that took the longest time to load (639 ms) relates to the external source

Additional info on


The browser has sent 63 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Professional Development Gilder Lehrman. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 27 to 1 for JavaScripts and from 6 to 1 for CSS and as a result speed up the page load time.











Possible request optimization













Normal result

IP address uses IP address which is currently shared with 4 other domains. The more sites share the same IP address, the higher the host server’s workload is. It is strongly recommended that the host server should be changed or the hosting provider should be requested to give a different (separate) IP address for this domain.

Poor result

IP Trace

DNS records

Type Host Target/ip TTL Other
A 299
A 299

299 Ipv6: 2400:cb00:2048:1::6818:51b

299 Ipv6: 2400:cb00:2048:1::6818:41b

Language and encoding

Good result


EN en language flag


EN en language flag





Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise 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 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.

HTTPS certificate

SSL Certificate has no SSL certificate. Web browsing can be safer with HTTPS connection, so we suggest that it should be obtained for this site.

Poor result

Visitor World Map

Country of origin for 87.2% of all visits is United States. It’s good for that their server is also located in United States, as that enables the majority of their visitors to benefit from a much faster page load time.

Good result

Poor result

Social Sharing Optimization

Open Graph description is not detected on the main page of Professional Development Gilder Lehrman. 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:

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