Monday, February 26, 2024
 Popular · Latest · Hot · Upcoming
62
rated 0 times [  64] [ 2]  / answers: 1 / hits: 56156  / 15 Years ago, tue, february 17, 2009, 12:00:00

I develop Joomla websites/components/modules and plugins and every so often I require the ability to use JavaScript that triggers an event when the page is loaded. Most of the time this is done using the window.onload function.



My question is:




  1. Is this the best way to trigger JavaScript events on the page loading or is there a better/newer way?

  2. If this is the only way to trigger an event on the page loading, what is the best way to make sure that multiple events can be run by different scripts?


More From » joomla

 Answers
14

window.onload = function(){}; works, but as you might have noticed, it allows you to specify only 1 listener.



I'd say the better/newer way of doing this would be to use a framework, or to just to use a simple implementation of the native addEventListener and attachEvent (for IE) methods, which allows you to remove the listeners for the events as well.



Here's a cross-browser implementation:



// Cross-browser implementation of element.addEventListener()
function listen(evnt, elem, func) {
if (elem.addEventListener) // W3C DOM
elem.addEventListener(evnt,func,false);
else if (elem.attachEvent) { // IE DOM
var r = elem.attachEvent(on+evnt, func);
return r;
}
else window.alert('I'm sorry Dave, I'm afraid I can't do that.');
}

// Use: listen(event name, elem, func);


For the window.onload case use: listen(load, window, function() { });






EDIT I'd like to expand my answer by adding precious information that was pointed by others.



This is about the DOMContentLoaded (Mozilla, Opera and webkit nightlies currently support this) and the onreadystatechange (for IE) events which can be applied to the document object to understand when the document is available to be manipulated (without waiting for all the images/stylesheets etc.. to be loaded).



There are a lot of hacky implementations for cross-browsers support of this, so I strongly suggest to use a framework for this feature.


[#99959] Tuesday, February 10, 2009, 15 Years  [reply] [flag answer]
Only authorized users can answer the question. Please sign in first, or register a free account.
blair

Total Points: 384
Total Questions: 108
Total Answers: 86

Location: Northern Ireland
Member since Tue, May 5, 2020
4 Years ago
blair questions
Sat, Feb 12, 22, 00:00, 2 Years ago
Wed, Aug 25, 21, 00:00, 3 Years ago
Sat, Jul 10, 21, 00:00, 3 Years ago
Tue, Aug 25, 20, 00:00, 4 Years ago
;