Edit:
Here is a viable replacement for jQuery ready
function ready(callback){ // in case the document is already rendered if (document.readyState!='loading') callback(); // modern browsers else if (document.addEventListener) document.addEventListener('DOMContentLoaded', callback); // IE <= 8 else document.attachEvent('onreadystatechange', function(){ if (document.readyState=='complete') callback(); }); } ready(function(){ // do something });
Taken from https://plainjs.com/javascript/events/running-code-when-the-document-is-ready-15/
Another good domReady function here taken from https://stackoverflow.com/a/9899701/175071
As the accepted answer was very far from complete, I stitched together a "ready" function like jQuery.ready()
based on jQuery 1.6.2 source:
var ready = (function(){ var readyList, DOMContentLoaded, class2type = {}; class2type["[object Boolean]"] = "boolean"; class2type["[object Number]"] = "number"; class2type["[object String]"] = "string"; class2type["[object Function]"] = "function"; class2type["[object Array]"] = "array"; class2type["[object Date]"] = "date"; class2type["[object RegExp]"] = "regexp"; class2type["[object Object]"] = "object"; var ReadyObj = { // Is the DOM ready to be used? Set to true once it occurs. isReady: false, // A counter to track how many items to wait for before // the ready event fires. See #6781 readyWait: 1, // Hold (or release) the ready event holdReady: function( hold ) { if ( hold ) { ReadyObj.readyWait++; } else { ReadyObj.ready( true ); } }, // Handle when the DOM is ready ready: function( wait ) { // Either a released hold or an DOMready/load event and not yet ready if ( (wait === true && !--ReadyObj.readyWait) || (wait !== true && !ReadyObj.isReady) ) { // Make sure body exists, at least, in case IE gets a little overzealous (ticket #5443). if ( !document.body ) { return setTimeout( ReadyObj.ready, 1 ); } // Remember that the DOM is ready ReadyObj.isReady = true; // If a normal DOM Ready event fired, decrement, and wait if need be if ( wait !== true && --ReadyObj.readyWait > 0 ) { return; } // If there are functions bound, to execute readyList.resolveWith( document, [ ReadyObj ] ); // Trigger any bound ready events //if ( ReadyObj.fn.trigger ) { // ReadyObj( document ).trigger( "ready" ).unbind( "ready" ); //} } }, bindReady: function() { if ( readyList ) { return; } readyList = ReadyObj._Deferred(); // Catch cases where $(document).ready() is called after the // browser event has already occurred. if ( document.readyState === "complete" ) { // Handle it asynchronously to allow scripts the opportunity to delay ready return setTimeout( ReadyObj.ready, 1 ); } // Mozilla, Opera and webkit nightlies currently support this event if ( document.addEventListener ) { // Use the handy event callback document.addEventListener( "DOMContentLoaded", DOMContentLoaded, false ); // A fallback to window.onload, that will always work window.addEventListener( "load", ReadyObj.ready, false ); // If IE event model is used } else if ( document.attachEvent ) { // ensure firing before onload, // maybe late but safe also for iframes document.attachEvent( "onreadystatechange", DOMContentLoaded ); // A fallback to window.onload, that will always work window.attachEvent( "onload", ReadyObj.ready ); // If IE and not a frame // continually check to see if the document is ready var toplevel = false; try { toplevel = window.frameElement == null; } catch(e) {} if ( document.documentElement.doScroll && toplevel ) { doScrollCheck(); } } }, _Deferred: function() { var // callbacks list callbacks = [], // stored [ context , args ] fired, // to avoid firing when already doing so firing, // flag to know if the deferred has been cancelled cancelled, // the deferred itself deferred = { // done( f1, f2, ...) done: function() { if ( !cancelled ) { var args = arguments, i, length, elem, type, _fired; if ( fired ) { _fired = fired; fired = 0; } for ( i = 0, length = args.length; i < length; i++ ) { elem = args[ i ]; type = ReadyObj.type( elem ); if ( type === "array" ) { deferred.done.apply( deferred, elem ); } else if ( type === "function" ) { callbacks.push( elem ); } } if ( _fired ) { deferred.resolveWith( _fired[ 0 ], _fired[ 1 ] ); } } return this; }, // resolve with given context and args resolveWith: function( context, args ) { if ( !cancelled && !fired && !firing ) { // make sure args are available (#8421) args = args || []; firing = 1; try { while( callbacks[ 0 ] ) { callbacks.shift().apply( context, args );//shifts a callback, and applies it to document } } finally { fired = [ context, args ]; firing = 0; } } return this; }, // resolve with this as context and given arguments resolve: function() { deferred.resolveWith( this, arguments ); return this; }, // Has this deferred been resolved? isResolved: function() { return !!( firing || fired ); }, // Cancel cancel: function() { cancelled = 1; callbacks = []; return this; } }; return deferred; }, type: function( obj ) { return obj == null ? String( obj ) : class2type[ Object.prototype.toString.call(obj) ] || "object"; } } // The DOM ready check for Internet Explorer function doScrollCheck() { if ( ReadyObj.isReady ) { return; } try { // If IE is used, use the trick by Diego Perini // http://javascript.nwbox.com/IEContentLoaded/ document.documentElement.doScroll("left"); } catch(e) { setTimeout( doScrollCheck, 1 ); return; } // and execute any waiting functions ReadyObj.ready(); } // Cleanup functions for the document ready method if ( document.addEventListener ) { DOMContentLoaded = function() { document.removeEventListener( "DOMContentLoaded", DOMContentLoaded, false ); ReadyObj.ready(); }; } else if ( document.attachEvent ) { DOMContentLoaded = function() { // Make sure body exists, at least, in case IE gets a little overzealous (ticket #5443). if ( document.readyState === "complete" ) { document.detachEvent( "onreadystatechange", DOMContentLoaded ); ReadyObj.ready(); } }; } function ready( fn ) { // Attach the listeners ReadyObj.bindReady(); var type = ReadyObj.type( fn ); // Add the callback readyList.done( fn );//readyList is result of _Deferred() } return ready; })();
How to use:
<script> ready(function(){ alert('It works!'); }); ready(function(){ alert('Also works!'); }); </script>
I am not sure how functional this code is, but it worked fine with my superficial tests. This took quite a while, so I hope you and others can benefit from it.
PS.: I suggest compiling it.
Or you can use http://dustindiaz.com/smallest-domready-ever:
function r(f){/in/.test(document.readyState)?setTimeout(r,9,f):f()} r(function(){/*code to run*/});
or the native function if you only need to support the new browsers (Unlike jQuery ready, this won't run if you add this after the page has loaded)
document.addEventListener('DOMContentLoaded',function(){/*fun code to run*/})