Related
I have a form on my page. If it is changed because beforeunload event the user will have a dialog which catch the leave process.
If the user click on "continue" or "leave" then the new page is loading and form's data are lost.
If the user click on "cancel" the leave process is canceled.
How can we know when the user has clicked on cancel ?
Why I need to know that ?
In my case I have a switch button. When the user turns it on, the script tries to reload the page. If the user click on "continue" or "leave" it's ok. But if the user click on "cancel" I would like show back the switch on the position "off".
When a user changes the button position ON and then attempts to leave but then cancel, the state of the button should change to OFF. We can use window.onbeforeunload function and returning false within the block of its code. Please see the below example, note that I have used checkbox instead of toggle switch, but you can type anything inside the window.onbeforeunload function to your desire.
window.onbeforeunload = () => {
document.getElementById("checkbox").checked = false;
return false;
}
.checkbox {
margin-top: 20px;
margin-left: 20px;
}
<p>Clicking the link below should prompt with "Leave" or "Cancel" option. If you check the box, then click on the link, and then click on "Cancel", the checkbox should return to false.</p>
<div>
Click here to exit this site and go to google.com
</div>
<div class="checkbox">
<input type="checkbox" id="checkbox">
</div>
To handle the state of the button, we can use localStorage and setInterval timer to check if the user has left the site and onbeforeunload event to prompt user to leave or cancel. When user cancels, the interval counts down to 0, this means the user is still on your site and updates the localStorage, but if left, the interval will not continue and doesn't change the localStorage value, and therefore, when returning to your site, the checked button should be updated to the previous position. Note that, when you click Run code snippet on this site, it might not work for localStorage, run this code from your site or on JSFiddle. :-)
window.onload = () => {
// declaration & Initialization
const input = document.createElement("input");
const defaultCounterValue = 10; // incremental --
const defaultIntervalValue = 50; // ms
const checkbox = document.getElementById('checkbox');
const setLocalStorage = (itemName, itemValue) => {
localStorage.setItem(itemName, itemValue);
};
const getLocalStorage = (itemName) => {
return localStorage.getItem(itemName) === null ? false : localStorage.getItem(itemName) === 'false' ? false : true;
};
let interval = undefined;
let counter = defaultCounterValue;
setLocalStorage('checkbox', getLocalStorage('checkbox').toString());
setTimeout(() => {
checkbox.checked = getLocalStorage('checkbox');
}, 0);
checkbox.addEventListener('click', () => {
setLocalStorage('checkbox', checkbox.checked);
});
// set input property and event handlers
input.type = 'checkbox';
input.checked = false;
input.style.display = 'none';
input.addEventListener('click', () => {
let removeInterval = () => {
clearInterval(interval);
interval = undefined;
}
if (interval) {
removeInterval();
}
interval = setInterval(() => {
if (input.checked === true) {
if (counter === 0) {
checkbox.checked = false;
setLocalStorage('checkbox', checkbox.checked);
counter = defaultCounterValue;
input.checked = false;
}
counter--;
} else {
removeInterval();
}
}, defaultIntervalValue);
});
document.body.appendChild(input);
// Event that run before the user leaves
window.onbeforeunload = (event) => {
event.preventDefault = true;
event.cancelBubble = true;
event.returnValue = null;
input.checked = false;
input.click();
};
}
.checkbox {
margin-top: 20px;
margin-left: 20px;
}
<p>Clicking the link below should prompt with "Leave" or "Cancel" option. If you check the box, then click on the link, and then click on "Cancel", the checkbox should return to false.</p>
<div>
Click here to exit this site and go to google.com
</div>
<div class="checkbox">
<input type="checkbox" id="checkbox">
</div>
I am very new to javascript and only know bare basics. I have an HTML checkbox which is powered by javascript to toggle and untoggle fullscreen. The problem I am facing is I don't know how to make it so if someone exits the fullscreen after toggling fullscreen using escape or f11, how do I make it so the checkbox automatically unchecks. Please provide me an exact script <3.
Here is what I have so far: https://codepen.io/SkylixMC/pen/JmJwVL
I have tried using this script with out any success:
var el = document.getElementById('fullscreen');
if (el.checked == true){
document.onfullscreenchange = function ( event ) {
el.checked = false;
};
}) );
Took me a lot longer than I thought this would.
Following this I was able to work out the below:
elem.addEventListener("mozfullscreenchange",function(){
if (document.mozFullScreen == false) {
document.getElementById("fullscreen").checked = false;
}
}, false);
elem.addEventListener("webkitfullscreenchange",function(){
if (document.webkitIsFullScreen == false) {
document.getElementById("fullscreen").checked = false;
}
}, false);
Here is a live example
let fullScreen = false
window.onkeydown = e =>{
if(fullScreen & e.keyCode==122 || e.keyCode==27){
//here you clear stuff , couse user wants to exit
console.log("exitFullScreen")
fullScreen = false
}
}
window.onresize = _=> {if((screen.availHeight-70 || screen.height-70) <= window.innerHeight && "fullscreen"){
fullScreen = true
console.log("enteringFullScreen")
}}
Live Example
I want to make the checkbox work more or less like a radio button in this instance. This is what I have so far. I would like to be able to do this in the treeCheckboxClicked() function so that it would just uncheck all the remaining checkboxs then check the one that was selected.
buildTocTree: function (cp1) {
var self = this;
var toc = new TOC({
checkboxes: false,
enableDelete: true,
deleteRecursive: true,
showRoot: false,
checkBoxes: false,
}, self._viewId + '_tocTree');
toc.on("checkBoxClick", dojo.hitch(this, "treeCheckboxClicked"));
},
treeCheckboxClicked: function (e) {
if (e.checked) {
if (e.subLayers || e.name === 'GISLayer')
this.selectedLayerValue('');
else if (e.layerInfos)
this.selectedLayerValue('');
else
this.selectedLayerValue(e.name);
if (this.selectedLayerValue() != '')
this._selectedGISSourceLayer = e;
else
this._selectedGISSourceLayer = '';
}
}
Without knowing the internal details of the TOC widget, especially its DOM, it's difficult to know how to query all checkboxes within its template. Assuming your treeCheckboxClicked is already getting called, and e.target is the checkbox element itself, the following code should get you close to your desired functionality:
if (e.checked) {
query('checkbox', self.domNode).forEach(function (checkbox) {
checkbox.checked = checkbox != e.target;
});
//...
}
Note: This assumes the dojo/query module has been loaded.
Are you using agsjs.TOC? They have a handler included to do this for you. In the examplesat http://gmaps-utility-gis.googlecode.com/svn/tags/agsjs/latest/examples/toc.html they toggle the function off and on with a button, but you can make it default on and include the following snippet in your tree declaration. (replace DynaLayer 1 with your layer)
toc.on('toc-node-checked', function(evt){
// when check on one layer, turn off everything else on the public safety service.
if (evt.checked && evt.rootLayer && evt.serviceLayer && evt.rootLayer == dynaLayer1){
evt.rootLayer.setVisibleLayers([evt.serviceLayer.id])
}
I have some pages with forms in my application.
How can I secure the form in such a way that if someone navigates away or closes the browser tab, they should be prompted to to confirm they really want to leave the form with unsaved data?
Short, wrong answer:
You can do this by handling the beforeunload event and returning a non-null string:
window.addEventListener("beforeunload", function (e) {
var confirmationMessage = 'It looks like you have been editing something. '
+ 'If you leave before saving, your changes will be lost.';
(e || window.event).returnValue = confirmationMessage; //Gecko + IE
return confirmationMessage; //Gecko + Webkit, Safari, Chrome etc.
});
The problem with this approach is that submitting a form is also firing the unload event. This is fixed easily by adding the a flag that you're submitting a form:
var formSubmitting = false;
var setFormSubmitting = function() { formSubmitting = true; };
window.onload = function() {
window.addEventListener("beforeunload", function (e) {
if (formSubmitting) {
return undefined;
}
var confirmationMessage = 'It looks like you have been editing something. '
+ 'If you leave before saving, your changes will be lost.';
(e || window.event).returnValue = confirmationMessage; //Gecko + IE
return confirmationMessage; //Gecko + Webkit, Safari, Chrome etc.
});
};
Then calling the setter when submitting:
<form method="post" onsubmit="setFormSubmitting()">
<input type="submit" />
</form>
But read on...
Long, correct answer:
You also don't want to show this message when the user hasn't changed anything on your forms. One solution is to use the beforeunload event in combination with a "dirty" flag, which only triggers the prompt if it's really relevant.
var isDirty = function() { return false; }
window.onload = function() {
window.addEventListener("beforeunload", function (e) {
if (formSubmitting || !isDirty()) {
return undefined;
}
var confirmationMessage = 'It looks like you have been editing something. '
+ 'If you leave before saving, your changes will be lost.';
(e || window.event).returnValue = confirmationMessage; //Gecko + IE
return confirmationMessage; //Gecko + Webkit, Safari, Chrome etc.
});
};
Now to implement the isDirty method, there are various approaches.
You can use jQuery and form serialization, but this approach has some flaws. First you have to alter the code to work on any form ($("form").each() will do), but the greatest problem is that jQuery's serialize() will only work on named, non-disabled elements, so changing any disabled or unnamed element will not trigger the dirty flag. There are workarounds for that, like making controls readonly instead of enabling, serializing and then disabling the controls again.
So events seem the way to go. You can try listening for keypresses. This event has a few issues:
Won't trigger on checkboxes, radio buttons, or other elements that are being altered through mouse input.
Will trigger for irrelevant keypresses like the Ctrl key.
Won't trigger on values set through JavaScript code.
Won't trigger on cutting or pasting text through context menus.
Won't work for virtual inputs like datepickers or checkbox/radiobutton beautifiers which save their value in a hidden input through JavaScript.
The change event also doesn't trigger on values set from JavaScript code, so also won't work for virtual inputs.
Binding the input event to all inputs (and textareas and selects) on your page won't work on older browsers and, like all event handling solutions mentioned above, doesn't support undo. When a user changes a textbox and then undoes that, or checks and unchecks a checkbox, the form is still considered dirty.
And when you want to implement more behavior, like ignoring certain elements, you'll have even more work to do.
Don't reinvent the wheel:
So before you think about implementing those solutions and all required workarounds, realize you're reinventing the wheel and you're prone to running into problems others have already solved for you.
If your application already uses jQuery, you may as well use tested, maintained code instead of rolling your own, and use a third-party library for all of this.
jquery.dirty (suggested by #troseman in the comments) provides functions for properly detecting whether a form has been changed or not, and preventing the user from leaving the page while displaying a prompt. It also has other useful functions like resetting the form, and setting the current state of the form as the "clean" state. Example usage:
$("#myForm").dirty({preventLeaving: true});
An older, currently abandoned project, is jQuery's Are You Sure? plugin, which also works great; see their demo page. Example usage:
<script src="jquery.are-you-sure.js"></script>
<script>
$(function() {
$('#myForm').areYouSure(
{
message: 'It looks like you have been editing something. '
+ 'If you leave before saving, your changes will be lost.'
}
);
});
</script>
Custom messages not supported everywhere
Do note that since 2011 already, Firefox 4 didn't support custom messages in this dialog. As of april 2016, Chrome 51 is being rolled out in which custom messages are also being removed.
Some alternatives exist elsewhere on this site, but I think a dialog like this is clear enough:
Do you want to leave this site?
Changes you made may not be saved.
Leave Stay
Check out the JavaScript onbeforeunload event. It's non-standard JavaScript introduced by Microsoft, however it works in most browsers and their onbeforeunload documentation has more information and examples.
Universal solution requiring no configuration that automatically detects all input modification, including contenteditable elements:
"use strict";
(() => {
const modified_inputs = new Set;
const defaultValue = "defaultValue";
// store default values
addEventListener("beforeinput", (evt) => {
const target = evt.target;
if (!(defaultValue in target || defaultValue in target.dataset)) {
target.dataset[defaultValue] = ("" + (target.value || target.textContent)).trim();
}
});
// detect input modifications
addEventListener("input", (evt) => {
const target = evt.target;
let original;
if (defaultValue in target) {
original = target[defaultValue];
} else {
original = target.dataset[defaultValue];
}
if (original !== ("" + (target.value || target.textContent)).trim()) {
if (!modified_inputs.has(target)) {
modified_inputs.add(target);
}
} else if (modified_inputs.has(target)) {
modified_inputs.delete(target);
}
});
// clear modified inputs upon form submission
addEventListener("submit", (evt) => {
modified_inputs.clear();
// to prevent the warning from happening, it is advisable
// that you clear your form controls back to their default
// state with evt.target.reset() or form.reset() after submission
});
// warn before closing if any inputs are modified
addEventListener("beforeunload", (evt) => {
if (modified_inputs.size) {
const unsaved_changes_warning = "Changes you made may not be saved.";
evt.returnValue = unsaved_changes_warning;
return unsaved_changes_warning;
}
});
})();
via jquery
$('#form').data('serialize',$('#form').serialize()); // On load save form current state
$(window).bind('beforeunload', function(e){
if($('#form').serialize()!=$('#form').data('serialize'))return true;
else e=null; // i.e; if form state change show warning box, else don't show it.
});
You can Google JQuery Form Serialize function, this will collect all form inputs and save it in array. I guess this explain is enough :)
Built on top of Wasim A.'s excellent idea to use serialization. The problem there was that the warning was also shown when the form was being submitted. This has been fixed here.
var isSubmitting = false
$(document).ready(function () {
$('form').submit(function(){
isSubmitting = true
})
$('form').data('initial-state', $('form').serialize());
$(window).on('beforeunload', function() {
if (!isSubmitting && $('form').serialize() != $('form').data('initial-state')){
return 'You have unsaved changes which will not be saved.'
}
});
})
It has been tested in Chrome and IE 11.
Based on the previous answers, and cobbled together from various places in stack overflow, here is the solution I came up with which handles the case when you actually want to submit your changes:
window.thisPage = window.thisPage || {};
window.thisPage.isDirty = false;
window.thisPage.closeEditorWarning = function (event) {
if (window.thisPage.isDirty)
return 'It looks like you have been editing something' +
' - if you leave before saving, then your changes will be lost.'
else
return undefined;
};
$("form").on('keyup', 'textarea', // You can use input[type=text] here as well.
function () {
window.thisPage.isDirty = true;
});
$("form").submit(function () {
QC.thisPage.isDirty = false;
});
window.onbeforeunload = window.thisPage.closeEditorWarning;
It's worth noting that IE11 seems to require that the closeEditorWarning function returns undefined for it not to show an alert.
The following one-liner has worked for me.
window.onbeforeunload = s => modified ? "" : null;
Just set modified to true or false depending on the state of your application.
You can use serialize() to create a URL encoded text string by serializing form values and check whether the form has changed beforeunload
$(document).ready(function(){
var form = $('#some-form'),
original = form.serialize()
form.submit(function(){
window.onbeforeunload = null
})
window.onbeforeunload = function(){
if (form.serialize() != original)
return 'Are you sure you want to leave?'
}
})
Refer this link https://coderwall.com/p/gny70a/alert-when-leaving-page-with-unsaved-form
Written by Vladimir Sidorenko
Following code works great. You need to reach your form elements' input changes via id attribute:
var somethingChanged=false;
$('#managerForm input').change(function() {
somethingChanged = true;
});
$(window).bind('beforeunload', function(e){
if(somethingChanged)
return "You made some changes and it's not saved?";
else
e=null; // i.e; if form state change show warning box, else don't show it.
});
});
Tested Eli Grey's universal solution, only worked after I simplified the code to
'use strict';
(() => {
const modified_inputs = new Set();
const defaultValue = 'defaultValue';
// store default values
addEventListener('beforeinput', evt => {
const target = evt.target;
if (!(defaultValue in target.dataset)) {
target.dataset[defaultValue] = ('' + (target.value || target.textContent)).trim();
}
});
// detect input modifications
addEventListener('input', evt => {
const target = evt.target;
let original = target.dataset[defaultValue];
let current = ('' + (target.value || target.textContent)).trim();
if (original !== current) {
if (!modified_inputs.has(target)) {
modified_inputs.add(target);
}
} else if (modified_inputs.has(target)) {
modified_inputs.delete(target);
}
});
addEventListener(
'saved',
function(e) {
modified_inputs.clear()
},
false
);
addEventListener('beforeunload', evt => {
if (modified_inputs.size) {
const unsaved_changes_warning = 'Changes you made may not be saved.';
evt.returnValue = unsaved_changes_warning;
return unsaved_changes_warning;
}
});
})();
The modifications to his is deleted the usage of target[defaultValue] and only use target.dataset[defaultValue] to store the real default value.
And I added a 'saved' event listener where the 'saved' event will be triggered by yourself on your saving action succeeded.
But this 'universal' solution only works in browsers, not works in app's webview, for example, wechat browsers.
To make it work in wechat browsers(partially) also, another improvements again:
'use strict';
(() => {
const modified_inputs = new Set();
const defaultValue = 'defaultValue';
// store default values
addEventListener('beforeinput', evt => {
const target = evt.target;
if (!(defaultValue in target.dataset)) {
target.dataset[defaultValue] = ('' + (target.value || target.textContent)).trim();
}
});
// detect input modifications
addEventListener('input', evt => {
const target = evt.target;
let original = target.dataset[defaultValue];
let current = ('' + (target.value || target.textContent)).trim();
if (original !== current) {
if (!modified_inputs.has(target)) {
modified_inputs.add(target);
}
} else if (modified_inputs.has(target)) {
modified_inputs.delete(target);
}
if(modified_inputs.size){
const event = new Event('needSave')
window.dispatchEvent(event);
}
});
addEventListener(
'saved',
function(e) {
modified_inputs.clear()
},
false
);
addEventListener('beforeunload', evt => {
if (modified_inputs.size) {
const unsaved_changes_warning = 'Changes you made may not be saved.';
evt.returnValue = unsaved_changes_warning;
return unsaved_changes_warning;
}
});
const ua = navigator.userAgent.toLowerCase();
if(/MicroMessenger/i.test(ua)) {
let pushed = false
addEventListener('needSave', evt => {
if(!pushed) {
pushHistory();
window.addEventListener("popstate", function(e) {
if(modified_inputs.size) {
var cfi = confirm('确定要离开当前页面嘛？' + JSON.stringify(e));
if (cfi) {
modified_inputs.clear()
history.go(-1)
}else{
e.preventDefault();
e.stopPropagation();
}
}
}, false);
}
pushed = true
});
}
function pushHistory() {
var state = {
title: document.title,
url: "#flag"
};
window.history.pushState(state, document.title, "#flag");
}
})();
var unsaved = false;
$(":input").change(function () {
unsaved = true;
});
function unloadPage() {
if (unsaved) {
alert("You have unsaved changes on this page. Do you want to leave this page and discard your changes or stay on this page?");
}
}
window.onbeforeunload = unloadPage;
Short answer:
let pageModified = true
window.addEventListener("beforeunload",
() => pageModified ? 'Close page without saving data?' : null
)
The solution by Eerik Sven Puudist ...
var isSubmitting = false;
$(document).ready(function () {
$('form').submit(function(){
isSubmitting = true
})
$('form').data('initial-state', $('form').serialize());
$(window).on('beforeunload', function() {
if (!isSubmitting && $('form').serialize() != $('form').data('initial-state')){
return 'You have unsaved changes which will not be saved.'
}
});
})
... spontaneously did the job for me in a complex object-oriented setting without any changes necessary.
The only change I applied was to refer to the concrete form (only one form per file) called "formForm" ('form' -> '#formForm'):
<form ... id="formForm" name="formForm" ...>
Especially well done is the fact that the submit button is being "left alone".
Additionally, it works for me also with the lastest version of Firefox (as of February 7th, 2019).
Adding to te idea of #codecaster
you could add this to every page with a form (in my case i use it in global way so only on forms would have this warn) change his function to
if ( formSubmitting || document.getElementsByTagName('form').length == 0)
Also put on forms submit including login and in cancel buttons links so when person press cancel or submit the form won't trigger the warn also in every page witouth a form...
<a class="btn btn-danger btn-md" href="back/url" onclick="setFormSubmitting()">Cancel</a>
You could check for a detailed explanation here:
http://techinvestigations.redexp.in/comparison-of-form-values-on-load-and-before-close/
The main code:
function formCompare(defaultValues, valuesOnClose) {
// Create arrays of property names
var aPropsFormLoad = Object.keys(defaultValues);
var aPropsFormClose = Object.keys(valuesOnClose);
// If number of properties is different,
// objects are not equivalent
if (aPropsFormLoad.length != aPropsFormClose.length) {
return false;
}
for (var i = 0; i < aPropsFormLoad.length; i++) {
var propName = aPropsFormLoad[i];
// If values of same property are not equal,
// objects are not equivalent
if (defaultValues[aPropsFormLoad]+"" !== valuesOnClose[aPropsFormLoad]+"") {
return false;
}
}
// If we made it this far, objects
// are considered equivalent
return true;
}
//add polyfill for older browsers, as explained on the link above
//use the block below on load
for(i=0; i < document.forms[0].elements.length; i++){
console.log("The field name is: " + document.forms[0].elements[i].name +
" and it’s value is: " + document.forms[0].elements[i].value );
aPropsFormLoad[i] = document.forms[0].elements[i].value;
}
//create a similar array on window unload event.
//and call the utility function
if (!formCompare(aPropsOnLoad, aPropsOnClose))
{
//perform action:
//ask user for confirmation or
//display message about changes made
}
I did it differently, sharing here so that someone can get help, tested only with Chrome.
I wanted to warn user before closing the tab only if there are some changes.
<input type="text" name="field" value="" class="onchange" />
var ischanged = false;
$('.onchange').change(function () {
ischanged = true;
});
window.onbeforeunload = function (e) {
if (ischanged) {
return "Make sure to save all changes.";
}
};
Works good, but got an-other issue, when i submit the form i get the unwanted warning, i saw lots of workaround on it, this is because onbeforeunload fires before onsubmit thats why we can't handle it in onsubmit event like onbeforeunload = null, but onclick event of submit button fires before these both events, so i updated the code
var isChanged = false;
var isSubmit = false;
window.onbeforeunload = function (e) {
if (isChanged && (!isSubmit)) {
return "Make sure to save all changes.";
}
};
$('#submitbutton').click(function () {
isSubmit = true;
});
$('.onchange').change(function () {
isChanged = true;
});
I made following code. It can compare changes in all fields (except those marked with .ignoreDirty class) or optionally for currently visible fields only. It can be reinitialized for new fields added by Javascript. From that reason I save not the form status but the status of each control.
/* Dirty warning for forms */
dirty = (skipHiddenOrNullToInit) => {
/* will return True if there are changes in form(s)
for first initialization you can use both: .dirty(null) or .dirty() (ignore its result)
.dirty(null) will (re)initialize all controls - in addititon use it after Save if you stay on same page
.dirty() will initialize new controls - in addititon use it if you add new fields with JavaScript
then
.dirty() (or: .dirty(false)) says if data are changed without regard to hidden fields
.dirty(true) says if data are changed with regard to hidden fields (ie. fields with .d-none or .hidden class)
controls with .ignoreDirty class will be skipped always
previous about .d-none, .hidden, .ignoreDirty applies to the control itself and all its ancestors
*/
let isDirty = false;
let skipSelectors = '.ignoreDirty';
if (skipHiddenOrNullToInit) {
skipSelectors += ', .d-none, .hidden'
} else if (skipHiddenOrNullToInit === undefined) {
skipHiddenOrNullToInit = false;
}
$('input, select').each(
function(_idx, el) {
if ($(el).prop('type') !== 'hidden') {
let dirtyInit = $(el).data('dirty-init');
if (skipHiddenOrNullToInit === null || dirtyInit === undefined) {
try {
isChromeAutofillEl = $(el).is(":-webkit-autofill");
} catch (error) {
isChromeAutofillEl = false;
}
if (isChromeAutofillEl && $(el).data('dirty-init') === undefined) {
setTimeout(function() { // otherwise problem with Chrome autofilled controls
$(el).data('dirty-init', $(el).val());
}, 200)
} else {
$(el).data('dirty-init', $(el).val());
}
} else if ($(el).closest(skipSelectors).length === 0 && dirtyInit !== $(el).val()) {
isDirty = true;
return false; // breaks jQuery .each
}
}
}
);
return isDirty;
}
I have additional troubles with Chrome autofill values because it is difficult to initizialize and have them loaded already. So I do not initialize on page load but in any focusin event. (But: Maybe there is still problem with control values changed by JavaScript.) I use following code which I call at page load:
let init_dirty = (ifStayFunc) => {
/* ifStayFunc: optional callback when user decides to stay on page
use .clearDirty class to avoid warning on some button, however:
if the button fires JavaScript do't use .clearDirty class and instead
use directly dirty(null) in code - to be sure it will run before window.location */
$('input, select').on('focusin', function(evt) {
if (!$('body').data('dirty_initialized')) {
dirty();
$('body').data('dirty_initialized', true);
}
});
window.addEventListener('beforeunload', (evt) => {
if (dirty(true)) {
if (ifStayFunc) {
ifStayFunc();
}
evt.preventDefault();
evt.returnValue = ''; // at least Google Chrome requires this
}
});
$('.clearDirty').on('click', function(evt) {
dirty(null);
});
};
So, I add the .clearDirty class to the buttons which provide Save and that way I prevent the warning in this case.
Callback ifStayFunc allows me to do something if user will Stay on Page while he is warned. Typically I can show additional Save Button (if I have still visible only some default/primary button, which makes Safe+SomethingMore - and I want allow Save withou this "SomethingMore").
I'd like to track changes in inputs in a form via javascript. My intent is (but not limited) to
enable "save" button only when something has changed
alert if the user wants to close the page and something is not saved
Ideas?
Loop through all the input elements, and put an onchange handler on each. When that fires, set a flag which lets you know the form has changed. A basic version of that would be very easy to set up, but wouldn't be smart enough to recognize if someone changed an input from "a" to "b" and then back to "a". If it were important to catch that case, then it'd still be possible, but would take a bit more work.
Here's a basic example in jQuery:
$("#myForm")
.on("input", function() {
// do whatever you need to do when something's changed.
// perhaps set up an onExit function on the window
$('#saveButton').show();
})
;
Text form elements in JS expose a .value property and a .defaultValue property, so you can easily implement something like:
function formChanged(form) {
for (var i = 0; i < form.elements.length; i++) {
if(form.elements[i].value != form.elements[i].defaultValue) return(true);
}
return(false);
}
For checkboxes and radio buttons see whether element.checked != element.defaultChecked, and for HTML <select /> elements you'll need to loop over the select.options array and check for each option whether selected == defaultSelected.
You might want to look at using a framework like jQuery to attach handlers to the onchange event of each individual form element. These handlers can call your formChanged() code and modify the enabled property of your "save" button, and/or attach/detach an event handler for the document body's beforeunload event.
Here's a javascript & jquery method for detecting form changes that is simple. It disables the submit button until changes are made. It detects attempts to leave the page by means other than submitting the form. It accounts for "undos" by the user, it is encapsulated within a function for ease of application, and it doesn't misfire on submit. Just call the function and pass the ID of your form.
This function serializes the form once when the page is loaded, and again before the user leaves the page. If the two form states are different, the prompt is shown.
Try it out: http://jsfiddle.net/skibulk/ev5rE/
function formUnloadPrompt(formSelector) {
var formA = $(formSelector).serialize(), formB, formSubmit = false;
// Detect Form Submit
$(formSelector).submit( function(){
formSubmit = true;
});
// Handle Form Unload
window.onbeforeunload = function(){
if (formSubmit) return;
formB = $(formSelector).serialize();
if (formA != formB) return "Your changes have not been saved.";
};
// Enable & Disable Submit Button
var formToggleSubmit = function(){
formB = $(formSelector).serialize();
$(formSelector+' [type="submit"]').attr( "disabled", formA == formB);
};
formToggleSubmit();
$(formSelector).change(formToggleSubmit);
$(formSelector).keyup(formToggleSubmit);
}
// Call function on DOM Ready:
$(function(){
formUnloadPrompt('form');
});
Try
function isModifiedForm(form){
var __clone = $(form).clone();
__clone[0].reset();
return $(form).serialize() == $(__clone).serialize();
}
Hope its helps ))
If your using a web app framework (rails, ASP.NET, Cake, symfony), there should be packages for ajax validation,
http://webtecker.com/2008/03/17/list-of-ajax-form-validators/
and some wrapper on onbeforeunload() to warn users taht are about to close the form:
http://pragmatig.wordpress.com/2008/03/03/protecting-userdata-from-beeing-lost-with-jquery/
Detecting Unsaved Changes
I answered a question like this on Ars Technica, but the question was framed such that the changes needed to be detected even if the user does not blur a text field (in which case the change event never fires). I came up with a comprehensive script which:
enables submit and reset buttons if field values change
disables submit and reset buttons if the form is reset
interrupts leaving the page if form data has changed and not been submitted
supports IE 6+, Firefox 2+, Safari 3+ (and presumably Opera but I did not test)
This script depends on Prototype but could be easily adapted to another library or to stand alone.
$(document).observe('dom:loaded', function(e) {
var browser = {
trident: !!document.all && !window.opera,
webkit: (!(!!document.all && !window.opera) && !document.doctype) ||
(!!window.devicePixelRatio && !!window.getMatchedCSSRules)
};
// Select form elements that won't bubble up delegated events (eg. onchange)
var inputs = $('form_id').select('select, input[type="radio"], input[type="checkbox"]');
$('form_id').observe('submit', function(e) {
// Don't bother submitting if form not modified
if(!$('form_id').hasClassName('modified')) {
e.stop();
return false;
}
$('form_id').addClassName('saving');
});
var change = function(e) {
// Paste event fires before content has been pasted
if(e && e.type && e.type == 'paste') {
arguments.callee.defer();
return false;
}
// Check if event actually results in changed data
if(!e || e.type != 'change') {
var modified = false;
$('form_id').getElements().each(function(element) {
if(element.tagName.match(/^textarea$/i)) {
if($F(element) != element.defaultValue) {
modified = true;
}
return;
} else if(element.tagName.match(/^input$/i)) {
if(element.type.match(/^(text|hidden)$/i) && $F(element) != element.defaultValue) {
modified = true;
} else if(element.type.match(/^(checkbox|radio)$/i) && element.checked != element.defaultChecked) {
modified = true;
}
}
});
if(!modified) {
return false;
}
}
// Mark form as modified
$('form_id').addClassName('modified');
// Enable submit/reset buttons
$('reset_button_id').removeAttribute('disabled');
$('submit_button_id').removeAttribute('disabled');
// Remove event handlers as they're no longer needed
if(browser.trident) {
$('form_id').stopObserving('keyup', change);
$('form_id').stopObserving('paste', change);
} else {
$('form_id').stopObserving('input', change);
}
if(browser.webkit) {
$$('#form_id textarea').invoke('stopObserving', 'keyup', change);
$$('#form_id textarea').invoke('stopObserving', 'paste', change);
}
inputs.invoke('stopObserving', 'change', arguments.callee);
};
$('form_id').observe('reset', function(e) {
// Unset form modified, restart modified check...
$('reset_button_id').writeAttribute('disabled', true);
$('submit_button_id').writeAttribute('disabled', true);
$('form_id').removeClassName('modified');
startObservers();
});
var startObservers = (function(e) {
if(browser.trident) {
$('form_id').observe('keyup', change);
$('form_id').observe('paste', change);
} else {
$('form_id').observe('input', change);
}
// Webkit apparently doesn't fire oninput in textareas
if(browser.webkit) {
$$('#form_id textarea').invoke('observe', 'keyup', change);
$$('#form_id textarea').invoke('observe', 'paste', change);
}
inputs.invoke('observe', 'change', change);
return arguments.callee;
})();
window.onbeforeunload = function(e) {
if($('form_id').hasClassName('modified') && !$('form_id').hasClassName('saving')) {
return 'You have unsaved content, would you really like to leave the page? All your changes will be lost.';
}
};
});
I would store each fields value in a variable when the page loads, then compare those values when the user unloads the page. If any differences are detected you will know what to save and better yet, be able to specifically tell the user what data will not be saved if they exit.
// this example uses the prototype library
// also, it's not very efficient, I just threw it together
var valuesAtLoad = [];
var valuesOnCheck = [];
var isDirty = false;
var names = [];
Event.observe(window, 'load', function() {
$$('.field').each(function(i) {
valuesAtLoad.push($F(i));
});
});
var checkValues = function() {
var changes = [];
valuesOnCheck = [];
$$('.field').each(function(i) {
valuesOnCheck.push($F(i));
});
for(var i = 0; i <= valuesOnCheck.length - 1; i++ ) {
var source = valuesOnCheck[i];
var compare = valuesAtLoad[i];
if( source !== compare ) {
changes.push($$('.field')[i]);
}
}
return changes.length > 0 ? changes : [];
};
setInterval(function() { names = checkValues().pluck('id'); isDirty = names.length > 0; }, 100);
// notify the user when they exit
Event.observe(window, 'beforeunload', function(e) {
e.returnValue = isDirty ? "you have changed the following fields: \r\n" + names + "\r\n these changes will be lost if you exit. Are you sure you want to continue?" : true;
});
I've used dirtyforms.js. Works well for me.
http://mal.co.nz/code/jquery-dirty-forms/
To alert the user before closing, use unbeforeunload:
window.onbeforeunload = function() {
return "You are about to lose your form data.";
};
I did some Cross Browser Testing.
On Chrome and Safari this is nice:
<form onchange="validate()">
...
</form>
For Firefox + Chrome/Safari I go with this:
<form onkeydown="validate()">
...
<input type="checkbox" onchange="validate()">
</form>
Items like checkboxes or radiobuttons need an own onchange event listener.
Attach an event handler to each form input/select/textarea's onchange event. Setting a variable to tell you if you should enable the "save" button. Create an onunload hander that checks for a dirty form too, and when the form is submitted reset the variable:
window.onunload = checkUnsavedPage;
var isDirty = false;
var formElements = //Get a reference to all form elements
for(var i = 0; len = formElements.length; i++) {
//Add onchange event to each element to call formChanged()
}
function formChanged(event) {
isDirty = false;
document.getElementById("savebtn").disabled = "";
}
function checkUnsavedPage() {
if (isDirty) {
var isSure = confirm("you sure?");
if (!isSure) {
event.preventDefault();
}
}
}
Here's a full implementation of Dylan Beattie's suggestion:
Client/JS Framework for "Unsaved Data" Protection?
You shouldn't need to store initial values to determine if the form has changed, unless you're populating it dynamically on the client side (although, even then, you could still set up the default properties on the form elements).
You can also check out this jQuery plugin I built at jQuery track changes in forms plugin
See the demo here and download the JS here
If you are open to using jQuery, see my answer a similar question:
Disable submit button unless original form data has changed.
I had the same challenge and i was thinking of a common solution. The code below is not perfect, its from initial r&d. Following are the steps I used:
1) Move the following JS to a another file (say changeFramework.js)
2) Include it in your project by importing it
3) In your html page, whichever control needs monitoring, add the class "monitorChange"
4) The global variable 'hasChanged' will tell, if there is any change in the page you working on.
<script type="text/javascript" id="MonitorChangeFramework">
// MONITOR CHANGE FRAMEWORK
// ALL ELEMENTS WITH CLASS ".monitorChange" WILL BE REGISTERED FOR CHANGE
// ON CHANGE IT WILL RAISE A FLAG
var hasChanged;
function MonitorChange() {
hasChanged = false;
$(".monitorChange").change(function () {
hasChanged = true;
});
}
Following are the controls where I used this framework:
<textarea class="monitorChange" rows="5" cols="10" id="testArea"></textarea></br>
<div id="divDrinks">
<input type="checkbox" class="chb monitorChange" value="Tea" />Tea </br>
<input type="checkbox" class="chb monitorChange" value="Milk" checked='checked' />Milk</br>
<input type="checkbox" class="chb monitorChange" value="Coffee" />Coffee </br>
</div>
<select id="comboCar" class="monitorChange">
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="mercedes">Mercedes</option>
<option value="audi">Audi</option>
</select>
<button id="testButton">
test</button><a onclick="NavigateTo()">next >>> </a>
I believe there can be huge improvement in this framework. Comment/Changes/feedbacks are welcome. :)