Develop Reference

Select All Checkboxes while keeping track of manual selects jquery

I've been using a simple select all script for checkboxes for a while now that looks something like this:
<span id="select">Select All</span>
with
$('#select').click(function(event) {
var $that = $(this);
$('.checkbox').each(function() {
this.checked = $that.is(':checked');
});
});
It's fairly simple. It attaches to an onclick, loops through all the inputs with the class .checkbox and checks or unchecks them accordingly. However what I'd like to do now is make it a bit more user friendly adding the following functionality to it.
1) When the user click the link labeled "Select All" it should select all check boxes as normal, but then change the text to "Deselect All". Similarly, when the user clicks "Deselect All" the text would go back to "Select All".
2) If the users manually select all check boxes I'd like check for this scenario and update the text from Select All to Deselect All as well.

Your code is checking whether a <span> is :checked, which as far as I know is not possible. Perhaps I'm wrong, but in this answer I'll use a different approach to keeping track of that, a data attribute.
// initialize 'checked' property
$('#select').data('checked', false);
// make link control all checkboxes
$('#select').click(function(event) {
var $that = $(this);
var isChecked = ! $that.data('checked');
$that.data('checked', isChecked).html(isChecked ? 'Deselect All' : 'Select All');
$('.checkbox').prop('checked', isChecked);
});
// make checkboxes update link
$('.checkbox').change(function(event) {
var numChecked = $('.checkbox:checked').length;
if (numChecked === 0) {
$('#select').data('checked', false).html('Select All');
} else if (numChecked === $('.checkbox').length) {
$('#select').data('checked', true).html('Deselect All');
}
});

Not jquery, but here's what I'd do
var cb=document.getElementsByClassName('cb'); //get all the checkboxes
var selectAll=document.getElementById('selectAll'); //get select all button
function selectAllState(inputEle,selectAllEle){ //class to manage the states of the checkboxes
var state=1; //1 if button says select all, 0 otherwise;
var num=inputEle.length;
function allChecked(){ //see if all are checked
var x=0;
for(var i=0;i<num;i++){
if(inputEle[i].checked==true){
x+=1;
}
}
return x;
}
function handler(){ //if all checked or all unchecked, change select all button text
var y=allChecked()
if( y==num && state){
selectAllEle.innerHTML='Deselect All';
state=0;
} else if(y==0 && !state){
selectAllEle.innerHTML='Select All';
state=1;
}
}
for(var i=0;i<num;i++){
inputEle[i].addEventListener('change',handler); //listen for changes in checks
}
function checkAll(){ //function checks or unchecks all boxes
for(var i=0;i<num;i++){
inputEle[i].checked=state;
}
handler();
}
selectAll.addEventListener('click',checkAll); //listen for button click
}
var myState=new selectAllState(cb,selectAll); //instance the selectAllState class
This creates a javascript class to manage the states of all your checkboxes. It takes two arguments, the first being the array of checkboxes (which is what you get if you use getElementsByClassName), and the second being the select all button. The internal methods could be exposed using the this keyword if you want to be able to, for example, have a different part of the application select or deselect all the checkboxes.

Try breaking it down in several functions: Let's call the span toggle, as it can select and de-select all.
<span id="toggle">Select All</span>
And we'll have a function to select and de-select all of the values. No need to iterate through the list as prop sets the value for all elements
function SetAll(value){
$(".checkbox").prop("checked", value);
}
Then for the toggle button:
$("#toggle").click(function(){
if($(this).text() == "Select All"){
SetAll(true);
$(this).text("De-select All");
} else {
SetAll(false);
$(this).text("Select All");
}
});
Finally we need an onchange event for each checkbox:
$(".checkbox").change(function(){
var allCheckboxes = $(".checkbox");
var allChecked = $.grep(allCheckboxes, function(n,i){
return $(n).is(":checked");
}); //grep returns all elements in array that match criteria
var allUnchecked = $.grep(allCheckboxes, function(n,i){
return $(n)is(":checked");
},true); //invert=true returns all elements in array that do not match
// check the lengths of the arrays
if (allChecked.length == allCheckboxes.length)
$("#toggle").text("De-select All");
if (allUnchecked.length == allCheckboxes.length)
$("#toggle").text("Select All");
}):

jquery if else button issue

hi everyone i have a issue with jquery :
in my code i have two multiple selection one on the left one on the right and a button near the selection on the right and i when a click on it the text from the right is copiedinto an input this is already done.i can add or remove element from a list to another with two button :
add and remove . hope i have been clear
when the text is copiedinto the input i can't move it anymore unless another text is copied throught the button near the selection :
here is my jquery code :
if($('#rightoption:selected').val() === $("#chosen").val())
{
$('#remove').attr('disabled' ,'disabled');
}
else ($('#right option:selected').val() !==$("#chosen").val())
{
$('#remove').removeAttr('disabled');
}
chosen is the id for the input.
but the problem is that when i select something different from the thing in the input he still disabled the button remove

This :
else ($('#right option:selected').val() !==$("#chosen").val())
{
$('#remove').removeAttr('disabled');
}
is equivalent to
else {
$('#right option:selected').val() !==$("#chosen").val(); // this does nothing
}
$('#remove').removeAttr('disabled');
You probably wanted
if($('#right option:selected').val() === $("#chosen").val()){
$('#remove').attr('disabled' ,'disabled');
} else {
$('#remove').removeAttr('disabled');
}
or better :
$('#remove').prop(
'disabled', $('#right option:selected').val() === $("#chosen").val()
);
And I suppose the first test should have '#right option:selected' (note the space).

Hide buttons related to empty textareas (selecting issue)

I'm struggling with a jQuery selection: I have a table that contains these columns (more or less)
Name (input field)
Surname (input field)
Note (textarea)
Button (a button to submit the relative note)
I would like to hide all buttons whose textarea is empty (to avoid the submission). This is the table:
The DOM structure of the single row is quite simple (I think):
So, I would like to select something like "all buttons contained in a td that is a brother of a td that cointains an empty textarea"...anf anf...can I do that with a single jQuery selection or not? Thank you in advance.

Of course!
$("tr td textarea").each(function() {
if (this.value == "") {
$(this).closest("td").next("td").find("button").prop("disabled", true);
}
});

You could hide buttons onLoad with the next selector:
$('textarea:empty').parent().next('td').find('button').hide();
Or if you want to disable the buttons:
$('textarea:empty').parent().next('td').find('button').prop("disabled", true);
It would be useful to check if user has type something in the textarea while on the page, and enable or not the button:
$( $('textarea') ).blur(function() {
var button = $(this).parent().next('td').find('button');
if($(this).val() === ''){
button.prop("disabled", true);
}else{
button.prop("disabled", false);
}
});
You can check this fiddle with your table included:
http://jsfiddle.net/6B9XA/4/

try this
$('table textarea').change(function()
{
var thisval=$.trim($(this).html())
if(thisval=='')
{
$(this).parent().next().children('button').attr('disabled')
}
})

I think you should use it this way:
$("#yourtableid").find("textarea").each(function() {
if (this.value == "") {
$(this).closest("tr").find("button").prop("disabled", true);
}
});
"#yourtableid" this should be changed to your table id.
Selectors optimization for performance boost.

You can use filter() to get only the buttons who contains an empty textarea within that row
$('tr button').filter(function(){ // get all buttons
return $(this).closest('tr').find('textarea').val() == ''; // only return those that are empty
}).prop('disabled',true); // disable the buttons

Move options between two multi-select fields

I'm trying to do something like this answer: https://stackoverflow.com/a/6256910/1641189
However I want to do it with multi-select fields since they provide scroll bars.
Instead of having each item move as soon as it's clicked, like the answer link above, I am going to have two buttons between the two select fields.
Something like this: http://www.kj4ohh.com/stuff/selectfields.png
How would I do this in javascript/jquery?
How would I return the contents of both select fields back to my flask application?
EDIT:
I had tried the following javascript:
function assign(form)
{
for(i=0;i<form.unassigned.length;i++) {
if (form.unassigned.options[i].selected == true) {
form.assigned.add(form.unassigned.options[i]);
form.unassigned.remove(i);
}
}
//unselect all items
form.assigned.selectedIndex = -1
}
function unassign(form)
{
for(i=0;i<form.assigned.length;i++) {
if (form.assigned.options[i].selected == true) {
form.unassigned.add(form.assigned.options[i]);
form.assigned.remove(i);
}
}
//unselect all items
form.unassigned.selectedIndex = -1
}
but with strange results:
With this script, if you select an item from either select field and hit the appropriate assign/unassign button it works corectly.
If you select two items, only one is moved.
If you select more than two, one is moved, one stays put and the rest vanish.
However if I add an alert() line outputting the current selection being observed, it will produce an alert box for each item selected correctly.

You have to use jquery plugin for better result
http://loudev.com/

You may try this
​$(function(){
$('#toSel1, #toSel2').on('click', function(){
if($(this).attr('id')=='toSel2')
{
var l=$('#sel1 option:selected').length;
if(!l) {
alert("Option not selected !");
return false;
}
$('#sel1 option:selected').each(function(){
$('#sel2').append($(this));
});
}
else
{
var l=$('#sel2 option:selected').length;
if(!l) {
alert("Option not selected !");
return false;
}
$('#sel2 option:selected').each(function(){
$('#sel1').append($(this));
});
}
});
});​
DEMO.

Using JavaScript or jQuery, how do I check if select box matches original value?

Just wondering if there is any way to check if the value of a select box drop-down matches the original value at the time of page load (when the value was set using selected = "yes") ?
I guess I could use PHP to create the original values as JavaScript variables and check against them, but there are a few select boxes and I'm trying to keep the code as concise as possible!

That's not too hard at all. This will keep track of the value for each select on the page:
$(document).ready(function() {
$("select").each(function() {
var originalValue = $(this).val();
$(this).change(function() {
if ($(this).val() != originalValue)
$(this).addClass('value-has-changed-since-page-loaded');
else
$(this).removeClass('value-has-changed-since-page-loaded');
});
});
});
This will apply a new class value-has-changed-since-page-loaded (which presumably you'd rename to something more relevant) to any select box whose value is different than it was when the page loaded.
You can exploit that class whenever it is you're interested in seeing that the value has changed.

$(document).ready(function() {
var initialSelectValue = $('#yourselect').val();
// call this function when you want to check the value
// returns true if value match, false otherwise
function checkSelectValue() {
return $('#yourselect').val() === initialSelectValue;
}
});
PS. You should use selected="selected" not selected="yes".

On page load, create an array with the initial value of each select box indexed by name:
var select_values = [];
$(document).ready(function() {
$("select").each(function() {
select_values[$(this).attr('name')] = $(this).val();
});
});
later when you need to check if a value has changed:
function has_select_changed(name) {
return $("select[name="+name+"]").val() != select_values[name];
}

First, a snippet:
$('select').each(
function(){
if( this.options[ this.selectedIndex ].getAttribute('selected') === null ){
alert( this.name +' has changed!')
}
});
Now the explanation:
Assuming selectElement is a reference to a <select /> elementYou can check which option is selected using
selectElement.selectedIndex
To get the <option /> element which is currently selected, use
selectElement.options[ selectElement.selectedIndex ]
Now when you know which option element is selected you can find out if this element has the selected='selected' attribute (as in the source code, it doesn't change - this is not the same as .selected propery of a DOM node, which is true for the currently selected option element and changes when the selection is changed)