I want to check the login status of a user through an ajax request. Depending wether the user is logged in I want to display either the username/password input or the username. Currently the request is sent on body.onload and a prgoress indicator is shown until the response arrives. Is there a better way?
Let's assume that the requirements state that there should be no direct server side processing.
Assuming that you really want to check the login status via ajax... No.
This sounds like an operation that should be done on the server first, before the page is rendered. If someone has javascript disabled, what would happen?
I think this should be possible, but it is not recommended. The correct thing to do is have the server fully determine the content of the page before it is even sent.
If you're being held up by slow image downloads or other non-HTML content, check out one of the various JavaScript libraries. I always recommend jQuery, which has the following syntax:
$(document).ready(function() {
// The DOM is fully loaded now, but images might still be loading.
});
I believe that if you use inline javascript, it should be executed as soon as it's encountered:
<HTML><HEAD>...</HEAD>
<BODY>
<script>
document.write("This is written before anything else");
</script>
This come later.
</BODY>
</HTML>
If you don't want to depend on a toolkit, you can create your own DOMReady function that looks kinda like this:
/* Usage: DOMReady(ajaxFunc); */
function DOMReady(f) {
if (!document.all) {
document.addEventListener("DOMContentLoaded", f, false);
} else {
if (document.readystate == 'complete') {
window.setTimeout(f, 0);
}
else {
//Add event to onload just if all else fails
attachEvent(window, "load", f);
}
}
}
Or for a more complex solution: http://snipplr.com/view/6029/domreadyjs/