Imagine I define video-type node, which displays for example a title and description, along with the video itself. And imagine I have a block of video teasers, where each teaser links to one such video node. And imagine this block is added to the bottom of any page displaying a video-type node: when the user clicks on one of the video teasers, the page reloads with a new video-type node.
Finally, imagine all of the above but without having to reload the full page.
If you go to http://whitehouse.gov/video, you will see what I am trying to accomplish. When you click on one of the video teasers, the url changes to the url for the new node, but the full page does not reload. Only the top section of the page, displaying the new node, gets reloaded.
My question: How do they do this?? How can I load the node content into a particular div on page, without reloading the entire page?
You can use hook_menu to implement a MENU_CALLBACK to it's own handler function in Drupal. You would return JSON or XML or an HTML fragment or whatever you want with the HTML for the new video. Then use JS to update the DOM with the new content received from the server. Updating the URL can be done with JS as well.
So basically you are going to handle video clicks on the client side with JS. The JS would make a request to your MENU_CALLBACK and you would receive whatever data you choose to implement back from the server. JS takes the data and updates the DOM.
With something like jQuery, you could use the $.get method and use the success attribute to update the window history in modern browsers.
Related
I have javascript files defined in the <head> of both my layout decorator template and my individual pages which are decorated. When I update a thymeleaf fragment in one of my pages the javascript defined in the head of the parent page no longer works. Is there a standard way to 'refresh' these js files?
Thanks.
Additional clarification :
I have a form submitted by an ajax call which updates a table in the page. I have a Jquery onClick function targeting a button in the updated table. The javascript doesn't seem able to bind to the returned elements in the updated part of the page. I select by element class and can see that the selection works prior to the partial fragment render.
For me it is unclear what you mean by
javascript defined in the head of the parent page no longer works.
The page is created on the server. Normally it contains urls of the javascript files
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
In this case 'refreshing' the javascript files can happen only in the client.
Check the html of the page in the client.
Are the tags as expected ?
Are there tags for all expected javascript files ?
With the browser tools (for example Google Chrom developer tools ) check that all script files are actually loaded.
If this doesnt help, it could be that the order of the script tags has changed between the first and second load. This could cause a different behaviour of the javascript executed in the browser.
EDIT :
With the initial load you bind javascript callbacks to dom elements.
You do this directly or through Jquery or other libraries.
When a new dom element is loaded, it has no callbacks bound to it, even if it has the same id as a replaced dom element.
So after the load you have to bind your callbacks again.
If you bound them 'by hand', just bind it again.
If you are using a JQuery plugin, that made the bindings, look into the code or documentation, many of them have a function for that or you can call initialization again.
Once you added new content to the DOM you need to bind again the new content.
Let's say I have a button with some class, the event in binded to the class:
<button class="someclass">Button 1</button>
<script>
var something = function() {
// do something
};
$(".someclass").on("click", something);
</script>
If I add more buttons from the same class to the DOM, they will have not have the click event binded. So once you load the new content via ajax, also remove all binding and add again (you need to remove or you will have buttons with 2 events).
$(".someclass").off("click");
$(".someclass").on("click" , something);
is it possible to delay loading of some controls on an xpage?
This is the problem: let's say you have a control that does a fultextsearch and displays the result in a repeat control. this ft search might take a long time and will hold the webpage loading in a waiting state until the search result is ready.
I want my page to load most of the data initally, and some "time consuming" controls should be loaded in to the page as a sperate request after the inital load.
this way the user will immediatly see the webpage, but some of the data on the page will load a little bit later without holding the webpage in a waiting state from the server.
possible?
The downside to using rendered is that all the value bindings will still evaluate, even if the corresponding markup isn't sent to the page. So the trick here is making sure the components don't even exist until you want them to.
Every component has a getChildren() method. This returns a mutable List of components, which has a add() method. This allows you to add components to the page on the fly, either while the page is loading, or later during an event. For the purposes of what you're trying to do, you would want to defer adding the "expensive" components until a subsequent event.
Create an event handler attached directly to the view root (), give it a unique ID (e.g. "loadExpensiveComponentsEvent", set its refresh mode to partial, set a refresh ID to whatever div or panel will contain the search results, and set its event name to an arbitrary event (e.g. "loadExpensiveComponents"). This prevents your event from being triggered by actual user behavior. Set the event's code to SSJS that will inject your components.
Then add a script block () to trigger the event after the page has loaded:
XSP.addOnLoad(function(){
XSP.firePartial(null, "#{id:loadExpensiveComponentsEvent}");
});
Your page will load without the search result components. Once the page has fully loaded, it will trigger the component injection event automatically.
For guidance on how to code the injection event, open the Java file that has been generated from your existing page to see what components need to be injected and what to set their values to.
You can pack them into a panel and set their rendered status to rendered=#{viewScope.pageFullyLoaded}. Then in the onLoad event have a XSP. partialRefresh request where you set viewScope.pageFullyLoaded=true
A little ugly but doable. Now you can wrap that code into your own custom control, so you could have a "lazyGrid", "lazyPanel" etc.
Not sure why I did not think of this before. the dynamic content control in extlib actually solves this problem. the dcc can be triggered onClientLoad both using javascript and ssjs afer the page has loaded.
one problem I am facing now is that I am already using the dcc on my site so I need to put another dcc within my dcc. and this seem to be a bit buggy. I have reported it to the extlib team on openNTF.
This is probably going to get a resounding no, but I am wondering if it possible to have the URl change dynamically with using hashing, and without invoking a http request from the browser?
My client is keen on using AJAX for main navigation. This is fine, when the end user goes to the front page first, but when they want to use the deep linking, despite it working, it forces an extra load time as the page loads the front page, then invokes the AJAX from the hash.
UPDATE: Could it be possible, given that what I want to avoid is the page reload (the reason is that it looks bad) to stem the reload by catching the hash with PHP before the headers are sent, and redirecting before the page load. This way only one page loads, and the redirect is all but invisible to the user. Not sure how to do this, but seems like it is possible?
Yes, this is possible. I often do this to store state in the hash part of the URL. The result is that the page doesn't reload, but if the user does reload, they're taken to the right page.
Using this method, the URL will look like: "/index#page=home" or "/index#page=about"
You'll need to write a JavaScript function that handles navigation, and you'll need a containing div that gets rewritten with the contents fetched from AJAX.
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<div id="content"></div>
<script type="text/javascript">
function link(page) {
location.hash = "page="+page;
loadPage(page);
}
// NOTE: This is using MooTools. Use the AJAX method in whatever
// JavaScript framework you're using.
function loadPage(page) {
new Request.HTML({
url: "/ajax/"+page+".html",
onSuccess: function(tree, elements, html) {
document.id('content').setProperty('html', html);
}
}).get();
}
</script>
Now, you'll also need to have something that checks the hash on page load to load the right content initially. Again, this is using MooTools, but use whatever onLoad method your JavaScript framework provides.
<script type="text/javascript">
document.addEvent('domready', function() {
parts = location.hash.split('=');
loadPage(parts[1]);
}
</script>
Ok, the problem is that opening an AJAX link of the form http://example.com/#xyz results in a full page being downloaded to the browser, and then the AJAX-altered content is changed once the page has loaded and checked the hash part of its URL. The user has a diconcerting experience.
You can hugely improve this by making a page that just contains the static elements - menus, etc. - and a loading GIF in the content area. This page checks its URL upon loading and dynamically fetches the content specified by the hash part. The page can have any URL you want; we'll use http://example.com/a. Links to this page (http://example.com/a#xyz) now provide a good user experience for users with scripting enabled.
However, new users won't come to the site by fetching http://example.com/a; they'll fetch http://example.com. This is fine - serve the full page, including the home page content and links that don't require scripting to work (e.g., http://example.com/xyz). A script run on loading this page should alter the href of AJAXable links to their AJAX form (http://example.com/a#xyz); thus the first link a user clicks on will result in a full page load but subsequent ones won't.
The only remaining problem is is a no-script user gets sent an AJAX link. You can add a noscript block to the AJAX page that contains a message explaining the problem and provides a link back to the homepage; you could include instructions on how to enable scripting or even how to modify the link by removing a# and pressing enter.
It's not a great answer, but you can offer a different link in the page itself; e.g., if the address bar shows /#xyz you include a link to /xyz somewhere in the page. You could also add a link or button that uses script to bookmark the page, which would again use the non-AJAX form of the link.
I have a page where a user can upload a file along with some other input. Because I wanted this to be AJAX-like, I resorted to using an iFrame to accomplish this.
After the file is uploaded and an iFrame is loaded with a response page, I need to update a DIV outside of the iFrame with an AJAX call. The reason for separate updates, is that the result of the outside DIV depends on the input that the user provided with the file input.
Can this be done? Am I approaching this the wrong way?
Thank you!
UPD: Can the returned client code from within the iFrame "see" elements outside that iFrame?
Write your code in the onload event of the page loaded into the iframe. Then top will give you the top frame or parent will give you the parent frame.
Yes , it can be done. But you can do away with,the need for an AJAX-call , to update the outside the div.
Have your, servlet(assuming you are using JSP/servlets) that accepts the mutlipart request(the servlet that accepts the upload), return the intended response (to be shown on the refreshed iFrame), and ALONG WITH IT, the necessary information from the file input. This way you have all the necessary details on the client, in one response. A simple javascript function can achieve , updating the outer div with the information from the file input.
Good day,
I was wondering if there is a way to make Ajax move on to the next code segment only when all the elements included in the server-side code page are fully loaded. When the retrieved data is text-only there’s no problem, but sometimes there are photos included.
This is part of the code I have been using:
xajx.onreadystatechange = function(){
if(xajx.readyState==4){
document.all.div1.innerHTML = xajx.responseText;
document.all.div1.style.display = “”;
}
}
The thing is that when the response is retrieved (readyState set to 4) and div1 is displayed, the Photo has not been completely loaded yet, so actually the user can see the process of the picture slowly appearing, as he would in any other “normal” case. What I want to do is making div1 available for display only once all the components are fully loaded while meanwhile the system does its stuff in the background. Before Ajax I used hidden iframes like everybody, so I could enclose an onload event handler within the iframe tag (or in an external script), so div1 would appear only after the iframe has fully loaded, photos included.
Any idea?
You can use the 'onload' event on images themselves. You'll need to work out how to attach that event when you are downloading the code dynamically as in your case.