I need to update an element on the page based on what the user is typing, while the user is typing (i.e. without having the user to click submit buttons). Similar to how StackOverflow does the preview of the question, but I need data from the server to update the element, hence the postback requirement.
What is the best way to get this done? Thanks!
There is no postback in MVC. Instead of postback you should make an ajax request using jquery to get data from server.
Examples of MVC + jquery JSON ajax request can be found here and here.
Related
I trying to add some fields to form depending of checkbox. But I have no idea how can I do that. I think Ajax can be useful, but I dont work with Ajax in Symfony2 yet, and if my form build up not in the controller what value I need specify in url: option of Ajax?
That's quite a broad question, but essentially: the Symfony way is to add them to the Form in the Controller by reacting to FormEvents.
Symfony Docs on Form Events
One way to achieve what you're after is to submit the form twice - the first time code will react to the checked checkbox and arrange the rest of the form as required, the second time the form will be valid and you can take action. Details on the above link. AJAX might help with this, allowing a form submission as soon as you've checked the checkbox.
Although you can create HTML form fields using AJAX, when you submit the form those fields need to exist in the Form object. You can add them just in time, in the controller, before Symfony tries to bind them.
I'm pretty new to Play Framework.
My problem is that when a user clicks on the register link, he will instantly see validation errors.
The problem is that the method that serves the form also validates the form. So when the user clicks on the register link, gets to the validation without any input and then gets validation errors.
One solution would be to have an extra method to only serve the register form. But this would require an extra form and an extra route.
Another solution would be to disable validation on empty forms.
Is this possible? If not is there an other way?
You are on the way to a good solution. Make a second method.
GET /register controllers.RegistrationController.showRegistration()
POST /register controllers.RegistrationController.register()
The first is to display the registration page with the form, the latter to handle the form submit.
A method should stick to do one thing: either to show a registration page or to handle a post. Generally it's not a good idea to write a single method with a lots of if-then-else flow control statements.
Play framework also supports REST principles: in a simplified way GET is to retrieve a resource (=an empty registration page here), POST is to submit data(=do the registration).
Have a good look at Play framework's examples, I think the computer-database is very simple and a good starting point for you.
I have a jsp form which takes in user details. On submit button it goes to a jsp page where the details are entered into the database. But before that I would like to check if the username is available as soon as the user clicks the check availability button. How can this be done?
2 ways:
Just redisplay the same page after submitting the form wherein you conditionally display the validation message. This is rather trivial and already covered in the Hello World example in our Servlets wiki page.
Use Ajax to send an asynchronous HTTP request and manipulate the HTML DOM based on the response of the request. This requires a bit more in depth understanding of how websites really work and what JavaScript is. You can find some concrete examples in How to use Servlets and Ajax?
Use AJAX(Asynchronous Javascript and Xml). Its the best web2.0 technology. You can manipulate DOM based on the answer from server
I'm looking to pass data from a form into an iFrame, but I have a slight problem.
The form page I can edit with no restrictions
The page I send the data to I cannot edit unless its html or JavaScript
The data needs to end up in an iframe within this page, which I can edit with no restrictions
I'm incorporating a search function into a CMS system which is why I cannot edit the iframe's parent page, and why I am using iframes at all.
At the moment the data sends to the parent page but is not picked up within the iframe, I am sending via the POST method.
I got it..
Added and extra page which converted the post data into session data,
if anyone knows a better way i would like to hear it though.
And they are the same domain, but editing the CMS system would have taken ages to look through as its not mainstream or developed by me.
Maybe I'm oversimplifying the problem, but can't you use the "target" attribute of the form tag to post to the Iframe?
I would like to have a user redirected to an external credit card gate. Of course I have to POST some user info to that gate, but I don't know how exactly can I do this.
I know that I could do this by generating a html form with hidden or read-only fields and have a user click "Submit" button. But this solution is not perfect, because all the form data could be easily changed using e.g. Firebug. I think you cannot do this using $this->_redirect(...). But maybe there is some other solution?
Many thanks for any tips or suggestions.
I would like to have a user redirected to an external credit card gate. Of course I have to POST some user info to that gate, but I don't know how exactly can I do this.
Using a form is the only method available. The RFC states that the user should explicitly agree to sending a POST (i.e. click on a submit button).
I know that I could do this by generating a html form with hidden or read-only fields and have a user click "Submit" button. But this solution is not perfect, because all the form data could be easily changed using e.g.
It is no more secure that using a redirect as the header data can be modified without too much of a problem. There are even Firefox plugins to do it.
use cURL to post data
http://framework.zend.com/manual/en/zend.http.client.adapters.html