So I'm able to successfully integrate AJAX requests with Spring MVC. However, I have a problem- if I click the "submit" button of my form, my #Controller class detects the url and returns a ModelAndView. However, what I want is that there be an AJAX check first, and if the form submission is not successful (e.g., blank fields), return an AJAX response. Otherwise, proceed as per normal and display a ModelAndView. However, I have no clue how to integrate both at the same time.
Any ideas or tutorials are appreciated.
Thanks!
You have several choices:
submit the form to a specific, different URL, when using AJAX
add a specific parameter to the request when posting using AJAX, and use this specific parameter to check if the request is n AJAX request
test if the X-Requested-With request header is present and contains XMLHttpRequest
I would go the PJAX route or what's also known as HiJax.
Basically you return a subset of the page if it's an AJAX request using headers. Most people than just use conditions in their view/template to decide to include the full or chrome-less HTML.
Related
I know two ways of submitting form data: by having a button of type submit or by an AJAX post call. What is the difference between those two regarding performace?
This is a very general question, so here is a very general answer.
If you implement the AJAX call efficiently on the server, then you can expect AJAX to be more performant (when measured on the server) than a full page round-trip.
For instance, if you use ASP.NET, clicking a button to submit a page will cause a POST of the form data and a complete re-buildup and rendering of the page. That is not necessary with an AJAX call, if you use real AJAX and not the Microsoft AJAX Control Toolkit for ASP.NET.
Better to use Ajax.BeginForm instead of Html.BeginForm. It will prevent the full postback and will improve the performance.
Ajax POST
Ajax post prevents reload and postback.İt sends data to controller.
Form Data
İt occurs reload page and postback.İt sends data to controller.
I am an average newbie to CakePHP. While reading cookbook found Ajax form and its submission. But it lacks more details.
What are the main difference between ajax form and a normal form or What are the more specific cases we need to use Ajax form over normal form?
An example will be appreciated
Thanks....
A properly implemented Ajax form is exactly the same as a regular form, except that if JavaScript is enabled a submit handler will be bound to it that will prevent the normal submission of the form and send the data using the XMLHttpRequest object. The response will then be processed by JavaScript in the current page instead of by loading an entirely new page.
This isn't necessarily a CakePHP question, it's understanding what AJAX is.
AJAX in layman's terms is basically submitting data to a website without reloading the current page. If this is the sort of feature you want, you'll need to look into the RequestHandler component and the JsHelper in the CakePHP book for the version you are using.
I have a PHP MVC Web App and Apache mod_rewrite rules already working fine, but when I create forms using method="get", the submitted URL looks like
contact/submit?a=b&c=d
I would like my form to submit to
contact/submit/a/b/c/d
Both posting and getting the form work fine on the server side, but when using post method, the back button always asks for reposting the form values and furthermore I want the strings in the URL for SEO. I think JQuery might let me intercept the form submit event and refresh to the url dynamically, but it it seems there must be an easier way to do it that I am missing.
You could use the POST->REDIRECT->GET pattern that Spring Web Flow utilizes. This would allow you to post as you wish and then redirect to contact/submit/a/b/c/d. It would also solve the problem with the back button asking you if you want to resubmit your form data. See this related article.
The GET method uses standard query string arguments to pass form data via an HTTP GET request.
The HTTP GET request is not intended to modify any data on the server. POST is designed for modifying data on the server.
GET may be cached. POST will not.
/a/b/c/d is not a standard format (as in RFC) for passing data. However, for requesting data or URLs to post to, that has become popular.
So, if you are updating server data, just use a POST -> REDIRECT -> /a/b/c/d.
If you are just reading data from the server, then you will need to use a bit of Javascript to read your form values and construct a query string, and then go to it with window.location = ...
Have fun!
I have many forms that use AJAX (w/ jQuery) for validation and data submission. When a form is filled out correctly, I use window.location to redirect the page after I get an acceptable response from the PHP script. On the new page, I use a session variable (set after the AJAX calls) to display the appropriate content. Please tell me if this is standard practice or please give me some suggestions.
Thanks!
Is there a reason you would use a $_SESSION variable to store the post-submission content? Standard practice would be to validate the form via AJAX but submit it in the standard way (i.e. via $_GET or $_POST) after validation. This way you don't need to store anything to a session and you'll likely have less to debug as you'll be submitting the form and displaying its results in the most widely-accepted way.
The benefit of AJAX is typically so that you can submit the form without actually having to do the redirect/refresh. You could get the same functionality by simply having your form POST to the destination URL, redirect to the appropriate place from there or send them back to the form displaying any errors that may have occurred. You could use AJAX to validate the form before the submission to save your users a redirection back to the form to fix their errors, but this is really just a convenience for them. Also, you will have to validate any user data on the server side once it has been submitted, as you can't rely on client-side validation, so you might as well forget the AJAX validation.
What causes Firefox to follow a POST request with a GET request when submitting a form via the POST method? The GET method is sent to the same url as the POST method but without the request parameters.
If you change the form method to GET, it will result in two identical GET requests.
This is a bug in Firefox 3. This happens when the response to the POST contains an image tag with an empty source attribute. eg <img src=""/>
The URL POSTed to might be returning a Redirect -- that would cause a GET. This is commonly done so that the page can be refreshed without reposting.
Probably there is some javascript involved. The form is submitted as a result of an onclick event in an anchor with: href="..." onclick="..form.submit()"