I've tried several javascript functions here and there but it seems that none of them worked for me.
What I'm doing is displaying a tower, that has as many stages as the user wishes. This is basically creating HTML tags using Js for every stage and the last one is a checkbox.
The thing I'd like to do is that when I click on a checkbox, all the other ones that are over this one would check programmatically also. So this is what I did:
let event = new Event('click');
//Here, q is the maximum stage that the user set.
document.addEventListener('click', function(e) {
let readStr = e.target.id;
if (readStr.startsWith("checkboxFan") && e.isTrusted) {
for (let r=parseFloat(readStr.substr(-1))+1; r<=q; r++) {
document.getElementById("checkboxFan"+r).dispatchEvent(event);
}
}
}, false);
And it's finding the IDs well and doing what I want, but the dispatchEvent isn't working as expected. In fact, it's not working at all. Also, the "click()" function works but the isTrusted is triggered, which is not what I want because the checkbox has to be clicked by the user.
Any solutions?
I've written some code based on your description.
https://stackblitz.com/edit/js-poevax?file=index.js
document.addEventListener(
"click",
function(e) {
let readStr = e.target.id;
if (readStr.startsWith("checkboxFan") && e.target.checked) {
for (let r = parseFloat(readStr.substr(-1)) + 1; r <= q; r++) {
document.getElementById("checkboxFan" + r).checked = true;
}
}
},
false
);
You should check this page.
Input Checkbox checked Property
cheers!
I'm using AngularJS directive for list of checkboxes checklist-model but I need to keep at least one check box checked at all times.
I've changed the checklist-model.js by adding an if:
watch if(current.length > 1)
before removing a check:
scope.$watch(attrs.ngModel, function(newValue, oldValue) {
if (newValue === oldValue) {
return;
}
var current = getter(scope.$parent);
if (angular.isFunction(setter)) {
if (newValue === true) {
setter(scope.$parent, add(current, value, comparator));
} else {
if(current.length > 1)
{
setter(scope.$parent, remove(current, value, comparator));
}
}
}
if (checklistChange) {
checklistChange(scope);
}
});
The problem is that the UI has already changed to unchecked while the model did not change.
Anyone has an elegant suggestion (preferably without JQuery) on how to change the checkbox back to "checked" state, or even better to catch it before it changed to checked?
JSfiddle here, try to uncheck all and see that when the check boxes are all unchecked (what I'm trying to prevent) the model stays not empty (which is good but not enough)
This probably comes from asynchronous nature of angular and the library you are using. What I could find so far is some dirty workaround like this (jsfiddle): create an event where you track the clicks on input and do the following:
$scope.onclick = function(evt) {
if ($scope.user.roles.length === 1 && prevLength === 1) {
evt.preventDefault();
}
prevLength = $scope.user.roles.length;
};
then add it it to your element
ng-click="onclick($event)"
I don't say it's perfect but it works
A colleague of mine suggested to disable the checkbox once it's the only one selected, that way you both prevent the changing of the module (therefore the directive does not even need to change) and the UX is better as the user understands he can't uncheck it:
<input type="checkbox" checklist-model="user.roles" checklist-value="role.id" ng-disabled="shouldDisable(role.id)"> {{role.text}}
$scope.shouldDisable = function(roleId) {
var isDisabled = false;
if($scope.user.roles.length === 1) {
isDisabled = $scope.user.roles.indexOf(roleId) !== -1;
}
return isDisabled;
}
See answer in this JSfiddle
At this moment, the component does not support this, but there's a discussion to implement minlength/maxlength https://github.com/vitalets/checklist-model/issues/15 and then this would be simply implemented by using checklist-minlength=1.
I also edited your proposal to implement checklistBeforeChange. I will try to handle this too in the next batch. Implemented in v0.8.0.
A nicer version to #ozba answer using the array.some function:
public atLeastOneRowEnabled(row): boolean {
//at least one row is visible except the current line
return !this.rows.some(rowIterator => rowIterator.logical_name !== row.logical_name && rowIterator.isVisible);
}
I have the following snippets of code. Basically what I'm trying to do is in the 1st click function I loop through my cached JSON data and display any values that exist for that id. In the 2nd change function I capturing whenever one of the elements changes values (i.e. yes to no and vice versa).
These elements are all generated dynamically though the JSON data I'm receiving from a webservice. From my understanding that is why I have to use the .live functionality.
In Firefox everything works as expected (of course). However, in IE7 it does not. In IE7, if I select a radio button that displays an alert from the click function then it also adds to the array for the changed function. However, if the radio button does not do anything from the click function then the array is not added to for the change.
As I look at this code I'm thinking that I might be able to combine these 2 functions together however, right now I just want it to work in IE7.
$(document).ready(function () {
//This function is run whenever a 'radio button' is selected.
//It then goes into the CPItemMetaInfoList in the cached JSON data
//($.myglobals) and checks to see if there are currently any
//scripts to display.
$("input:radio").live("click", function () {
var index = parseInt(this.name.split(':')[0]);
for (i = 0; i <= $.myglobals.result.length - 1; i++) {
if ($.myglobals.result[i].CPItemMetaInfoList.length > 0) {
for (j = 0; j <= $.myglobals.result[i].CPItemMetaInfoList.length - 1; j++) {
if (index == $.myglobals.result[i].QuestionId) {
alert($.myglobals.result[i].CPItemMetaInfoList[j].KeyStringValue);
return;
}
}
}
}
});
});
$(document).ready(function () {
var blnCheck = false;
//Checks to see if values have changed.
//If a value has been changed then the isDirty array gets populated.
//This array is used when the questionSubmit button is clickeds
$('input').live('change', function () {
blnCheck = false;
for (i = 0; i <= isDirty.length - 1; i++) {
if (isDirty[i] == $(this).attr("name")) {
blnCheck = true;
break
}
}
if (blnCheck == false) {
isDirty[arrayCount] = $(this).attr("name");
arrayCount += 1;
alert($(this).attr("name"));
}
});
$('textarea').live('change', function () {
blnCheck = false;
for (i = 0; i <= isDirty.length - 1; i++) {
if (isDirty[i] == $(this).attr("id")) {
blnCheck = true;
break
}
}
if (blnCheck == false) {
isDirty[arrayCount] = $(this).attr("id");
arrayCount += 1;
//alert($(this).attr("name"));
}
});
});
UPDATE:
I had to move this chunk of code into the click function:
blnCheck = false;
for (i = 0; i <= isDirty.length - 1; i++) {
if (isDirty[i] == $(this).attr("name")) {
blnCheck = true;
break
}
}
if (blnCheck == false) {
isDirty[arrayCount] = $(this).attr("name");
arrayCount += 1;
alert($(this).attr("name"));
}
Like this:
$(document).ready(function () {
//This function is run whenever a 'radio button' is selected.
//It then goes into the CPItemMetaInfoList in the cached JSON data
//($.myglobals) and checks to see if there are currently any
//scripts to display.
$("input:radio").live("click", function () {
var index = parseInt(this.name.split(':')[0]);
for (i = 0; i <= $.myglobals.result.length - 1; i++) {
if ($.myglobals.result[i].CPItemMetaInfoList.length > 0) {
for (j = 0; j <= $.myglobals.result[i].CPItemMetaInfoList.length - 1; j++) {
if (index == $.myglobals.result[i].QuestionId) {
alert($.myglobals.result[i].CPItemMetaInfoList[j].KeyStringValue);
return;
}
}
}
}
blnCheck = false;
for (i = 0; i <= isDirty.length - 1; i++) {
if (isDirty[i] == $(this).attr("name")) {
blnCheck = true;
break
}
}
if (blnCheck == false) {
isDirty[arrayCount] = $(this).attr("name");
arrayCount += 1;
}
});
});
But...
I had to leave the change function the same. From my testing I found that the .click function worked for IE7 for the radio buttons and checkbox elements, but the .change functionality worked for the textboxes and textareas in IE7 and FF as well as the original functionality of the radio buttons and checkbox elements.
This one got real messy. Thanks to #Patricia for looking at it. Here suggestions did lead me to this solution. I'm going to leave the question unanswered as I wonder if there isn't a cleaner solution to this.
Fact: change event on radio buttons and checkboxes only get fired when the focus is lost (i.e. when the blur event is about to occur). To achieve the "expected" behaviour, you really want to hook on the click event instead.
You basically want to change
$('input').live('change', function() {
// Code.
});
to
$('input:radio').live('click', functionName);
$('input:not(:radio)').live('change', functionName);
function functionName() {
// Code.
}
(I'd however also take checkboxes into account using :checkbox selector for the case that you have any in your form, you'd like to treat them equally as radiobuttons)
I think this is because IE fires the change when focus is lost on checks and radios. so if the alert is popping up, focus is being lost and therefor the change event is firing.
EDIT:
try changing the $('input') selector to $('input:not(:radio)')
so the click will fire for your radios and the change for all your others.
Edit #2:
How bout putting the stuff that happens on change into a separate function. with the index as a parameter. then you can call that function from the change() and the click(). put the call to that function after your done with the click stuff.
You're declaring your blnCheck variable inside one of your document.ready() functions. You don't need two of these either, it could all be in one.
This means that the variable that you're declaring there won't be the one used when your change function is actually called, instead you're going to get some kind of implicit global. Don't know if this is part of it, but might be worth looking at. You should declare this at the top of your JS file instead.
I have written a game in java script and while it works, it is slow responding to multiple clicks. Below is a very simplified version of the code that I am using to handle clicks and it is still fails to respond to a second click of 2 if you don't wait long enough. Is this something that I need to just accept or is there a faster way to be ready for the next click?
BTW, I attach this function using AddEvent from the quirksmode recoding contest.
var selected = false;
var z = null;
function handleClicks(evt) {
evt = (evt)?evt:((window.event)?window.event:null);
if (selected) {
z.innerHTML = '<div class="rowbox a">a</div>';
selected = false;
} else {
z.innerHTML = '<div class="rowbox selecteda">a</div>';
selected = true;
}
}
The live code may be seen at http://www.omega-link.com/index.php?content=testgame
You could try to only change the classname instead of removing/adding a div to the DOM (which is what the innerHTML property does).
Something like:
var selected = false;
var z = null;
function handleClicks(evt)
{
var tmp;
if(z == null)
return;
evt = (evt)?evt:((window.event)?window.event:null);
tmp = z.firstChild;
while((tmp != null) && (tmp.tagName != 'DIV'))
tmp = tmp.firstChild;
if(tmp != null)
{
if (selected)
{
tmp.className = "rowbox a";
selected = false;
} else
{
tmp.className = "rowbox selecteda";
selected = true;
}
}
}
I think your problem is that the 2nd click is registering as a dblclick event, not as a click event. The change is happening quickly, but the 2nd click is ignored unless you wait. I would suggest changing to either the mousedown or mouseup event.
I believe your problem is the changing of the innerHTML which changes the DOM which is a huge performance problem.
Yeah you may want to compare the performance of innerHTML against document.createElement() or even:
el.style.display = 'block' // turn off display: none.
Profiling your code may be helpful as you A/B various refactorings:
http://www.mozilla.org/performance/jsprofiler.html
http://developer.yahoo.com/yui/profiler/
http://weblogs.asp.net/stevewellens/archive/2009/03/26/ie-8-can-profile-javascript.aspx
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. :)