A plain object or string that is sent to the server with the request. To see its working, add jQuery version for CDN before 3.0. It is used to specify the function to run after the document is loaded. Inserts a DOM element before all paragraphs. Now I have just changed the loading of my external js and css such that it is deferred (as recommended by Google https://developers.google.com/speed/docs/best-practices/payload?hl=en#DeferLoadingJS): This way the page is fully rendered, including all images, before it starts to load the JS. Should a Javascript function be written and called inside jQuery document ready or outside? Not the answer you're looking for? The code tries to load a website URL in an