Is it possible in Lift web framework to create forms (and links) that react via AJAX, but also work without Javascript support? If so, how?
When I build the form using <lift:form.ajax>, the form's action is set to javascript:// so that it no longer submits without JS. If I build the form without explicit AJAX support, I don't know how to insert the AJAX functionality.
I suppose I could build a RESTful interface (we'll have to build that anyway) and write custom Javascript to submit the form through that. I would like to avoid code duplication, though: if it is possible to handle all three inputs (RESTful, traditional HTTP POST, AJAX) with the same code, that would be best.
Take a look at http://demo.liftweb.net/form_ajax
FormWithAjax.scala
class FormWithAjax extends StatefulSnippet {
private var firstName = ""
private var lastName = ""
private val from = S.referer openOr "/"
def dispatch = {
case _ => render _
}
def render(xhtml: NodeSeq): NodeSeq =
{
def validate() {
(firstName.length, lastName.length) match {
case (f, n) if f < 2 && n < 2 => S.error("First and last names too short")
case (f, _) if f < 2 => S.error("First name too short")
case (_, n) if n < 2 => S.error("Last name too short")
case _ => S.notice("Thanks!"); S.redirectTo(from)
}
}
bind( "form", xhtml,
"first" -> textAjaxTest(firstName, s => firstName = s, s => {S.notice("First name "+s); Noop}),
"last" -> textAjaxTest(lastName, s => lastName = s, s => {S.notice("Last name "+s); Noop}),
"submit" -> submit("Send", validate _)
)
}
form_ajax.html
<lift:surround with="default" at="content">
Enter your first and last name:<br>
<form class="lift:FormWithAjax?form=post">
First Name: <form:first></form:first>
Last Name: <form:last></form:last>
<form:submit></form:submit>
</form>
</lift:surround>
And this will work without javascript:
<form action="/form_ajax" method="post">
<input name="F1069091373793VHXH01" type="hidden" value="true">
First Name: <input value="" type="text" name="F1069091373788OVAAWQ" onblur="liftAjax.lift_ajaxHandler('F1069091373789N2AO0C=' + encodeURIComponent(this.value), null, null, null)">
Last Name: <input value="" type="text" name="F1069091373790VANYVT" onblur="liftAjax.lift_ajaxHandler('F1069091373791CJMQDY=' + encodeURIComponent(this.value), null, null, null)">
<input name="F1069091383792JGBYWE" type="submit" value="Send">
</form>
I dont know a lot about Lift so my answer focuses on alternate way to do it.
This is jQuery based and will do with AJAX when Javascript is usable and traditional POST if there is no Javascript support enabled.
Form:
<form id="ajaxform" action="formhandler.php" method="post" enctype="multipart/form-data" >
<input name="firstname" type="text" />
<input name="email" type="email" />
<input name="accept" type="submit" value="Send" />
</form>
<div id="result"></div>
JS:
note: jQuery $.ajax() sends as application/x-www-form-urlencoded by default, it may be good to set form enctype="application/x-www-form-urlencoded" too.
$("#ajaxform").submit(function(e){
// Alternative way to prevent default action:
e.preventDefault();
$.ajax({
type: 'POST',
url: 'formhandler.php',
// Add method=ajax so in server side we can check if ajax is used instead of traditional post:
data: $("#ajaxform").serialize()+"&method=ajax",
success: function(data){ // formhandler.php returned some data:
// Place returned data <div id="result">here</div>
$("#result").html(data);
}
});
// Prevent default action (reposting form without ajax):
return false;
});
Server side (PHP)
<?php
if (isset($_POST['method']) && $_POST['method'] == 'ajax') {
// AJAX is used this time, only #result div is updating in this case.
} else {
// Traditional POST is used to send data, whole page is reloading. Maybe send <html><head>... etc.
}
?>
What About REST then?
This is something you should decide to use or to not use, it is not something to support as alternate to other methods (ajax, traditional) but more something integrate within other methods.
Of course you can always enable or disable REST feature.
You can always make form method="POST/GET/PUT/DELETE" and ajax call RESTful:
...
$.ajax({
type: 'PUT',
url: 'formhandler.php',
...
...
$.ajax({
type: 'DELETE',
url: 'formhandler.php',
...
But REST asks us to use XML, JSON, ... for requests too
Well, that is not well supported by browsers (without Javascript) but $.ajax() uses application/x-www-form-urlencoded as default encoding.
Ofcourse, with Javascript one can always convert data container to XML or JSON ...
Here's how it can be done with jQuery, JSON object:
/* This is function that converts elements to JSON object,
* $.fn. is used to add new jQuery plugin serializeObject() */
$.fn.serializeObject = function()
{
var o = {};
var a = this.serializeArray();
$.each(a, function() {
if (o[this.name]) {
if (!o[this.name].push) {
o[this.name] = [o[this.name]];
}
o[this.name].push(this.value || '');
} else {
o[this.name] = this.value || '';
}
});
return o;
};
But I want one AJAX call that does everything:
You are right, computers should do our work. It's what they are designed for.
So, another thing that needs to be done is to check what http method our original html form wants to use and adapt it to send ajax requests with same method that would be used without javascript support.
This is modified version from under JS: heading used earlier:
...
// Alternative way to prevent default action:
e.preventDefault();
// Find out what is method that form wants to use and clone it:
var restmethod = $('#ajaxform').attr('method');
// Put form data inside JSON object:
var data = $('#orderform').serializeObject();
// Add method=ajax so in server side we can check if ajax is used instead of traditional post:
data.method = 'ajax';
$.ajax({
type: restmethod, // Use method="delete" for ajax if so defined in <form ...>
url: 'formhandler.php',
data: data, // data is already serialized as JSON object
...
Now, our AJAX handler sends data as JSON object using method (post|get|put|delete) that is defined at <form method="put" ...>, if form method changes then our ajax handler will adapt changes too.
That's all, some code tested and is actually in use, some is not tested at all but should work.
Related
I have looked through all the similar posts out there but nothing seems to help. This is what I have
HTML:
<section>
<form id="contact-form" action="" method="post">
<fieldset>
<input id="name" name="name" placeholder="Name" type="text" />
<input id="email" name="email" placeholder="Email" type="text" />
<textarea id="comments" name="comments" placeholder="Message"></textarea>
<div class="12u">
Send Message
Clear Form
</div>
<ul id="response"></ul>
</fieldset>
</form>
</section>
JavaScript/jQuery:
function sendForm() {
var name = $('input#name').val();
var email = $('input#email').val();
var comments = $('textarea#comments').val();
var formData = 'name=' + name + '&email=' + email + '&comments=' + comments;
$.ajax({
type: 'post',
url: 'js/sendEmail.php',
data: formData,
success: function(results) {
$('ul#response').html(results);
}
}); // end ajax
}
What I am unable to do is prevent the page refresh when the #form-button-submit is pressed. I tried return false; I tried preventDefault() and every combination including return false; inside the onClick. I also tried using input type="button" and type="submit" instead and same result. I can't solve this and it is driving be nuts. If at all possible I would rather use the hyperlink due to some design things.
I would really appreciate your help on this.
Modify the function like this:
function sendForm(e){
e.preventDefault();
}
And as comment mentions, pass the event:
onclick = sendForm(event);
Update 2:
$('#form-button-submit').on('click', function(e){
e.preventDefault();
var name = $('input#name').val(),
email = $('input#email').val(),
comments = $('textarea#comments').val(),
formData = 'name=' + name + '&email=' + email + '&comments=' + comments;
$.ajax({
type: 'post',
url: 'js/sendEmail.php',
data: formData,
success: function(results) {
$('ul#response').html(results);
}
});
});
function sendForm(){
// all your code
return false;
}
I was also bit engaged in finding solution to this problem, and so far the best working method I found was this-
Try using XHR to send request to any url, instead of $.ajax()...I know it sounds bit weird but try it out!
Example-
<form method="POST" enctype="multipart/form-data" id="test-form">
var testForm = document.getElementById('test-form');
testForm.onsubmit = function(event) {
event.preventDefault();
var request = new XMLHttpRequest();
// POST to any url
request.open('POST', some_url, false);
var formData = new FormData(document.getElementById('test-form'));
request.send(formData);
This would send your data successfully ...without page reload.
Have you tried using
function sendForm(event){
event.preventDefault();
}
Simple and Complete working code
<script>
$(document).ready(function() {
$("#contact-form").submit(function() {
$("#loading").show().fadeIn('slow');
$("#response").hide().fadeOut('slow');
var frm = $('#contact-form');
$.ajax({
type: frm.attr('method'),
url: 'url.php',
data: frm.serialize(),
success: function (data) {
$('#response').html(data);
$("#loading").hide().fadeOut('slow');
$("#response").slideDown();
}, error: function(jqXHR, textStatus, errorThrown){
console.log(" The following error occured: "+ textStatus, errorThrown );
} });
return false;
});
});
</script>
#loading could be an image or something to be shown when the form is processing, to use the code simply create a form with ID contact-form
Another way to avoid the form from being submitted is to place the button outside of the form. I had existing code that was working and created a new page based on the working code and wrote the html like this:
<form id="getPatientsForm">
Enter URL for patient server
<br/><br/>
<input name="forwardToUrl" type="hidden" value="/WEB-INF/jsp/patient/patientList.jsp" />
<input name="patientRootUrl" size="100"></input>
<br/><br/>
<button onclick="javascript:postGetPatientsForm();">Connect to Server</button>
</form>
This form cause the undesirable redirect described above. Changing the html to what is shown below fixed the problem.
<form id="getPatientsForm">
Enter URL for patient server
<br/><br/>
<input name="forwardToUrl" type="hidden" value="/WEB-INF/jsp/patient/patientList.jsp" />
<input name="patientRootUrl" size="100"></input>
<br/><br/>
</form>
<button onclick="javascript:postGetPatientsForm();">Connect to Server</button>
I expect anyone to understand my idea very well as it's a very simple idea.
give your required form itself an id or you can get it by any other way you prefer.
in the form input "submit" call an onclick method from your javascript file.
in this method make a variable refer to your from id the addEventListener on it and make a preventDefault method on "submit" not on "click".
To clarify that see this:
// element refers to the form DOM after you got it in a variable called element for example:
element.addEventListener('submit', (e) => {
e.preventDefault();
// rest of your code goes here
});
The idea in brief is to deal with the form by submit event after dealing with submit button by click event.
Whatever is your needs inside this method, it will work now without refresh :)
Just be sure to deal with ajax in the right way and you will be done.
Of course it will work only with forms.
The way I approached this: I removed the entire form tag and placed all the form elements such as input, textarea tags inside a div and used one button to call a javascript function. Like this:
<div id="myform">
<textarea name="textarea" class="form-control">Hello World</textarea>
<button type="submit" class="btn btn-primary"
onclick="javascript:sendRequest()">Save
changes</button>
<div>
Javascript:
function sendRequest() {
$.ajax({
type: "POST",
url: "/some/url/edit/",
data: {
data: $("#myform textarea").val()
},
success: function (data, status, jqXHR) {
console.log(data);
if (data == 'success') {
$(`#mymodal`).modal('hide');
}
}
});
return true;
}
I thought why use a form when we are sending the actual request using AJAX. This approach may need extra effort to do things like resetting the form elements but it works for me.
Note:
The above answers are more elegant than this but my use case was a little different. My webpage had many forms and I didn't think registering event listeners to every submit button was a good way to go. So, I made each submit button call the sendRequest() function.
I need the value from the option to be assigned to my model once the user clicks on the specific option.
<select name="isEmailVerified" class="form-select">
<option value="" selected> all </option>
<option value="true"> verified </option>
<option value="false"> unverified </option>
</select>
expected value => #Model.IsEmailVerified.XXXXX(my value)
What I usually do when I want to asyncronously send data back and forth is this:
I take advantage of Tag Helpers as they're great and saves you a ton of boilerplate code, so I create a standard <form> element without an actual Submit button, just a div that looks like one. You might want to check official MSDN Documentation for the Select Tag Helper to create an appropriate model.
#model VerificationModel
<form asp-action="CheckEmail" method="post">
<select asp-for="IsEmailVerified" asp-items="Model.VerificationTypes">
<div id="SubmitCheck" class="btn">Check email</div>
</form>
Create a javascript function that takes care of the actual submitting chore. Since the form is created with the Tag Helpers, the request body will automatically bind
$('#SubmitCheck').on('click', function() {
let form = $(this).parents('form')[0];
let formData = new FormData(form);
let request = function () {
return fetch(form.getAttribute('action'), {
method: 'POST',
body: formData
});
};
let onresponse = function() {
// do some preliminary actions on 200 response
}
let callback = function() {
// deal with response result
}
let onerror = function() {
// deal with errors
}
request()
.then(response => onresponse())
.then(result => callback())
.fail(err => onerror());
})
Add the [FromForm] attribute to Controller props (model is the same used in the page) to ensure model binding
public async Task<CustomResultClass> CheckEmail([FromForm] VerificationModel model)
{
// do something
}
I want to implement a send mail form using Thymeleaf.
I have a page called start_page.html that contains this form :
<div class="w3-container w3-padding-64" id="contact">
<h1>Contact</h1><br>
<p>We offer full-service catering for any event, large or small. We understand your needs and we will cater the food to satisfy the biggerst criteria of them all, both look and taste. Do not hesitate to contact us.</p>
<p class="w3-text-blue-grey w3-large"><b>Catering Service, 42nd Living St, 43043 New York, NY</b></p>
<p>You can also contact us by phone 00553123-2323 or email catering#catering.com, or you can send us a message here:</p>
<form th:action="#{~/homePage/contact}" th:object="${contactMail}" method="post" target="_blank">
<p><input class="w3-input w3-padding-16" type="text" th:field="*{nom}" th:placeholder="#{homePage.nom}" required name="nom"></p>
<p><input class="w3-input w3-padding-16" type="text" th:field="*{prenom}" th:placeholder="#{homePage.prenom}" required name="prenom"></p>
<p><textarea class="w3-input w3-padding-16" type="text" th:field="*{message}" style="height: 250px;" th:placeholder="#{homePage.message}" required name="message"></textarea>
<p><button class="w3-button w3-light-grey w3-section" type="submit">[[#{homePage.envoyer}]]</button></p>
</form>
</div>
I have already implemented a controller for this form action
#Controller
#PropertySource(ignoreResourceNotFound = true , value = "classpath:messages.properties")
public class HomePageController {
#Autowired
private MailContactService mailService;
#RequestMapping(value = "/homePage/contact", method = RequestMethod.POST)
public String sendMessage(ContactMail contactMail){
mailService.sendContactMail(contactMail);
System.out.println("done");
return "/home/start_page";
}
}
I'm not getting the desired behavior: I though that my page will stay the same but my page is reloading.
I want to order the controller to do something without getting out of my page.
I googled and I found that I can send a service object to my page but I want to avoid this option if there is other solutions .
Thank you.
You'll need to use an AJAX call if you don't want to refresh your page.
What this means is that you want to intercept the default HTTP form post behavior (that will do a full page refresh) using javascript.
For this you need to :
Remove the action tag on your form (let javascript handle it when clicking the button to submit the form)
Add this to your page (will be executed when the form is submitted :
$(document).ready(function () {
$("#contact-form").submit(function (event) {
// do not post the form and trigger full page refresh
event.preventDefault();
var formData = .. // construct some formData
$.ajax({
type: "POST",
contentType: "application/json",
url: "/homePage/contact",
data: JSON.stringify(formData),
dataType: "json",
success: function (data) {
console.log("SUCCESS : ", data);
},
error: function (e) {
console.log("ERROR : ", e);
}
});
});
});
For a full example, as always, mkyong.com has got you covered :)
Is it possible to bind data from your model to a knockout viewmodel. Heres an example:
public ActionResult Edit(int id)
{
Product product = _db.Products.FirstOrDefault(x=>x.ItemId == id);
return View(product);
}
Then in the View I would traditionally do something like so:
#model myApp.Models.Product
#using(Html.BeginForm())
{
#Html.EditorFor(x=>x.ItemName)
#Html.ValidationMessageFor(x=>x.ItemName)
<input type="submit" value="Update" />
}
But with Knockout I would create a EditProductViewModel from where I would do something like:
var EditProductViewModel = {
ItemName = ko.observable('')
};
EditProductViewModel.Edit = function() {
$.ajax({
url: "Home/Edit",
data: ko.ToJson(this),
success: function() {
// do something
}
});
};
$(function() {
ko.applyBindings(EditProductViewModel);
});
And instead of using the Html Helpers I would do something like so in my view:
<form data-bind="submit: Edit">
<input type="text" data-bind="value: ItemName" />
<input type="submit" value="Update" />
</form>
So how can I populate this with the data returned from my controller?
I don't have a any experience with knockout but it would seem to me that you would no longer want to return a view from your controller how about
return JSON(product)
that way you would get a json element of the product on your javascript success function you would need to collected the json element
$.ajax({
url: "Home/Edit",
data: ko.ToJson(this),
success: function(data) {
// map to knockout view model
}
});
and then from here you would call the map bindings.
When using knockout you have two ways to do this.
1. Load your textboxes, etc in one view. Upon loading that view for the first time convert your model to JSON upon in initial load to use by knockout.
ALL additional calls to/from go via JSON.
You can use in your View:
#Html.Raw(Json.Encode(yourModel))
Load your textboxes in your view (ie they are part of your vieW)
Trigger off on document.ready() your ajax calls to get your data from your controller, convert to JSON ie return Json(yourModel, JsonRequestBehavior.AllowGet) and bind those results roughly as you are already doing above
Note - the downside with this approach is with validation. If you have all client side validation, then this is OK as the attributes for data-* will have been written out by MVC to your textboxes, etc. If you have any server side validation, there is no 'smooth' built in integration here with knockout.
There's a decent article here:
http://www.codeproject.com/Articles/305308/MVC-Techniques-with-JQuery-JSON-Knockout-and-Cshar
but still lacks on server side validation mention.
You could serialize data to your page and then initialize knockout viewmodel with values from server.
ItemName = ko.observable(serializedModel.ItemName);
I am using the ajaxform() plugin, which so far is working well. However, my input fields have default values, and if the user just submits the untouched form, I need to blank them out before the form is submitted using the beforeSubmit: callback.
In nutshell, I don't know the syntax to check the forms input fields and stop the submit if necessary. I have an idea its using the each() method and this.defaultValue, and maybe a return false? but I'm not sure of the details.
Could anyone perhaps give me an idea? Thanks. Heres my code so far, its the checkValues() function that I'm stuck with.
$(document).ready(function(){
//========= Functions =========
function styleForm() {
$('.quickcontact label').hide();
$('input[type="text"],textarea').addClass("idleField");
$('input[type="text"],textarea').focus(function() {
$(this).removeClass("idleField").addClass("focusField");
if (this.value == this.defaultValue){
this.value = '';
}
if(this.value != this.defaultValue){
this.select();
}
});
$('input[type="text"],textarea').blur(function() {
$(this).removeClass("focusField").addClass("idleField");
if ($.trim(this.value) == ''){
this.value = (this.defaultValue ? this.defaultValue : '');
}
});
}
//options for ajaxform() function
var options = {
target: '.quickcontactDisplay', // target element(s) to be updated with server response
beforeSubmit: checkValues, // pre-submit callback
success: reBind // post-submit callback
// other available options:
//url: url // override for form's 'action' attribute
//type: type // 'get' or 'post', override for form's 'method' attribute
//dataType: null // 'xml', 'script', or 'json' (expected server response type)
//clearForm: true // clear all form fields after successful submit
//resetForm: true // reset the form after successful submit
// $.ajax options can be used here too, for example:
//timeout: 3000
};
//rebinds the ajax functionality to updated form html
function reBind() {
// re-do the form, as it has just been replaced
$('form.quickcontact').ajaxForm(options);
styleForm();
}
//checks for default values of form on submit to prevent them being submitted
function checkValues(){
}
// ==== logic =====
$('form.quickcontact').ajaxForm(options);
styleForm();
});
And my form html:
<form action="/enquiries/add" method="post" id="EnquiryAddForm" class="quickcontact">
<input type="hidden" value="POST" name="_method"/>
<input type="hidden" id="EnquiryVisitorId" value="276" name="data[Enquiry][visitor_id]"/>
<input type="text" id="EnquiryName" maxlength="200" value="Your name" name="data[Enquiry][name]"/>
<input type="text" id="EnquiryEmailAddress" maxlength="200" value="Your Email" name="data[Enquiry][emailAddress]"/>
<textarea id="EnquiryEnquiry" rows="6" cols="30" name="data[Enquiry][enquiry]">Your Email Address</textarea>
<input type="submit" value="Ok, I'm done"/>
</form>
You are abusing the default value as a label. This is causing you problems. Rather then trying to work around those problems, I suggest fixing the cause instead.
When setting default values — set default values. Don't use the default value as a pseudo-label. Use a <label> element instead.
Haven't you looked at the documentation?
beforeSubmit:
Callback function to be invoked before the form is submitted. The
'beforeSubmit' callback can be
provided as a hook for running
pre-submit logic or for validating the
form data. If the 'beforeSubmit'
callback returns false then the form
will not be submitted. The
'beforeSubmit' callback is invoked
with three arguments: the form data in
array format, the jQuery object for
the form, and the Options Object
passed into ajaxForm/ajaxSubmit. The
array of form data takes the following
form:
[ { name: 'username', value: 'jresig' }, { name: 'password', value: 'secret' } ]
Default value: null
Here the idea, didn't check it yet.
function checkValues(formData, jqForm, options)
{
for( var i in formData)
if ( formData[i].value == "")
return false;
return true;
}
sounds as if you need to:
run through all the inputs / textarea at the start and grab the default values, then stick it into an associative array with the element id as key
within checkValues, iterate through inputs once again and compare the pre-submit value against your array - when finding a match, you can set the value to "".