However, let's say I want to run a function that is written in standard JavaScript with no library backing it, and that I want to launch a function as soon as the page is ready to handle it. What's the proper way to approach this? Or I can even try at the bottom of the page after everything, but the end body or html tag like:. The simplest thing to do in the absence of a framework that does all the cross-browser compatibility for you is to just put a call to your code at the end of the body.
This is faster to execute than an onload handler because this waits only for the DOM to be ready, not for all images to load. And, this works in every browser. If you need full cross browser compatibility including old versions of IE and you don't want to wait for window.
It's fairly involved depending upon the capabilities of the browser. And, there are some work-arounds in the IE code path that I don't quite follow, but it looks like it has something to do with frames.
Handlers registered with docReady are guaranteed to be fired in the order they were registered. If you call docReady fn after the document is already ready, the callback will be scheduled to execute as soon as the current thread of execution completes using setTimeout fn, 1. This allows the calling code to always assume they are async callbacks that will be called later, even if later is as soon as the current thread of JS finishes and it preserves calling order.
I'm even talking about latest version of Chrome browser! I would like to mention some of the possible ways here together with a pure javascript trick which works across all browsers :. The trick here, as explained by the original author , is that we are checking the document. If it contains the string in as in uninitialized and loading , the first two DOM ready states out of 5 we set a timeout and check again. Otherwise, we execute the passed function. And here's the jsFiddle for the trick which works across all browsers.
Thanks to Tutorialzine for including this in their book. I have just developed the following. It's a rather simplistic equivalent to jQuery or Dom ready without backwards compatibility.
It probably needs further refinement. I'll update if I find any issues. It's written to handle async loading of JS but you might want to sync load this script first unless you're minifying. 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.
Note: The document. Now let us see these things by practical examples of how this event works actually. Now, click on the Click Me button and it will give you the following alter box. Also, notice that our button element is placed at bottom of our script. But that is working perfectly fine as document ready event has not fired until the DOM elements are fully loaded. Now, with the above changes in place, run the code and you will get the following page and click on the Click Me button. R Programming.
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