Goals: Add links that are reasonable and good explanations of how stuff works. No hype and no vendor content if possible. Practical first-hand accounts of models in prod eagerly sought.

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.
Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.
elem.offsetLeft
, elem.offsetTop
, elem.offsetWidth
, elem.offsetHeight
, elem.offsetParent
var parser = document.createElement('a'); | |
parser.href = "http://example.com:3000/pathname/?search=test#hash"; | |
parser.protocol; // => "http:" | |
parser.hostname; // => "example.com" | |
parser.port; // => "3000" | |
parser.pathname; // => "/pathname/" | |
parser.search; // => "?search=test" | |
parser.hash; // => "#hash" | |
parser.host; // => "example.com:3000" |