title: Remotely investigating / measuring occasional slow loading speed of a dynamic page
body: <p>I've been getting reports from some visitors of one of my web sites that it loads for them pretty slowly, but I can't recreate this slowness from any of my different machines or  Internet connections.</p>
  
  <p>I've pretty much eliminated the server itself as being responsible for the slowness, so it could be anything from hosting provider problems, to CDN problems for specific ISPs/countries, to even (theoretically) some type of so called "internet protection suite" that subjects my web site to long scrutiny on the local machine of some of my visitors.   </p>
  
  <p>Are there any tools / methods that you can recommend to gain some insights about these mysterious slownesses?</p>
  
  <p>I guess I could use something like javascript code that would measure the load speed of each and every element in the page (including things like linked css/js files), and at the end of a complete load would post to the server the data. Then, I could collect the anomalous data and look for patterns in things like useragents, or, with registered users, I could contact them directly to try and get more hints. Is there perhaps some library that does something like that? </p>