Javascript when is document ready

I've found it useful in development. Modern browsers also support async loading of scripts which further enhances the experience.

Support for async means multiple scripts can be downloaded simultaneously all while still rendering the page. Just watch out when depending on other scripts loaded asynchronously or use a minifier or something like browserify to handle dependencies. The good folks at HubSpot have a resource where you can find pure Javascript methodologies for achieving a lot of jQuery goodness - including ready. Here's a cleaned-up, non-eval-using version of Ram-swaroop's "works in all browsers" variety--works in all browsers!

See also How to check if DOM is ready without a framework? Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 9 years, 7 months ago. Active 1 year, 6 months ago. Viewed 1.

Aryan Beezadhur 2, 1 1 gold badge 13 13 silver badges 36 36 bronze badges. See this: stackoverflow. Add a comment. Active Oldest Votes. To give you a little idea what jQuery does which will work wherever the script tag is placed. If supported, it tries the standard: document. Here is a full substitute for jQuery's. Declare a public function docReady fn, context When docReady fn, context is called, check if the ready handler has already fired.

If so, just schedule the newly added callback to fire right after this thread of JS finishes with setTimeout fn, 1. If the ready handler has not already fired, then add this new callback to the list of callbacks to be called later. Check if the document is already ready. If so, execute all ready handlers.

If we haven't installed event listeners yet to know when the document becomes ready, then install them now. If document. The "load" is a backup event for safety and should not be needed. In the onreadystatechange event, check to see if the document. In all the other event handlers, call a function to fire all the ready handlers. In the function to call all the ready handlers, check a state variable to see if we've already fired.

If we have, do nothing. If we haven't yet been called, then loop through the array of ready functions and call each one in the order they were added. Set a flag to indicate these have all been called so they are never executed more than once. Clear the function array so any closures they might be using can be freed. Jan Kyu Peblik 1, 11 11 silver badges 18 18 bronze badges. Tom Stickel Tom Stickel Ram Patra Ram Patra Very bad approach, using a timeout loop with an arbitrary 9ms interval, and using eval.

I'm not quite sure what you're asking, but maybe this can help: window. The official justification is:. This is because the selection has no bearing on the behavior of the. The ready event is fired when the DOM is fully loaded and accesses to elements are safe. The load event, on the other hand, is fired after the DOM and all assets have loaded. This waits not only for the DOM to be ready for interaction but also for images to be completely loaded which can take time, depending on the image sizes.

The ready method makes sure that code is only executed when all DOM elements are safe to be manipulated. But what does this mean? But, note that the callback will not be executed if the event has already fired.