jQuery单击事件与绑定事件

Question

Hi guys I am having a problem with Events. I have a checkbox list and I have a main check box that checks all boxes. When I clickEvent some of my checkbox list items it should add data-id attr to the "selected obj". So in my case when I press main check box to check all others every thing is ok (it simply clicks all other elements). but when i do that it empties my array. I mean if i uncheck it will be the way it supposed to be but checked (when uncheck it fills when i check it empties).

......    
var selected = {};
        var reload = function(){
            selected = {};
            $('.checkbox_all').unbind('click');
            $('.table_checkbox').unbind('click');
            $('.checkbox_all').bind('click', checkAll);
            $('.table_checkbox').bind('click', checkMe);
        }
        var checkMe = function(e){
            var checkbox = $(e.target);
            var id = checkbox.attr('data-id');
            //console.log(id);
            if(checkbox.attr('checked')){
                selected[id] = id;
            }else{
                if(selected[id]) delete selected[id];
            }
            console.log(selected);
        }
        var checkAll = function(e){
            if($(e.target).attr('checked')){
                $('.table_checkbox').each(function(){
                    if($(this).attr('checked') === false){
                        $(this).click();
                    }
                });
            }else{
                $('.table_checkbox').each(function(){
                    if($(this).attr('checked') === true){
                        $(this).click();
                    }
                });
            }
            //console.log(selected);
        }
.......

HTML:

       <tr><th class="table-header-check"><input type="checkbox" class="checkbox_all"/></th></tr>
    <tr class=""><td><input type="checkbox" data-id="5" class="table_checkbox"></td></tr>
    <tr class="alternate-row"><td><input type="checkbox" data-id="6" class="table_checkbox"</td></tr>
    <tr class="alternate-row"><td><input type="checkbox" data-id="8" 

....ETC\

My problem is that when i click .checkbox_all it should click on all .table_checkbox(that r cheched or uncheched)... it just clicks all checkboxes like a main checkbox... it works fine, but i have an event all other checkboxes if i click em i add some data to array when i unclick em it removes data from array.... so when im clicking checkboxes sepperatly they add /remove data to array properly... but when im clicking on main checkbox... it clicks on right checkboxes but the data array is empty when all checked and full when all unchecked... it must be the opposite way

Answer 1

Could you instead go for a cleaner solution, and generate selected on the fly? See here for an example (and a JSFiddle for everyone else): http://jsfiddle.net/turiyag/3AZ9C/

function selected() {
    var ret = {};
    $.each($(".table_checkbox"),function(index,checkbox) {
        if($(checkbox).prop("checked")) {
            ret[$(checkbox).prop("id")] = true;
        }
    });
    return ret;
}

** EDIT: **

If you're looking to have an array that is added to and removed from, then this JSFiddle ( http://jsfiddle.net/turiyag/pubGb/ ) will do the trick. Note that I use prop() instead of attr(), in most cases, especially this one, you should use prop() to get the value you want.

Answer 2

To work with your own code you need to understand the order of events. When you programmatically call click() on the checkbox the javascript (checkMe() for children) executes before the state of each child checkbox is changed (eg, adding attribute 'checked'). It is because of this reason that the checkMe() function was adding and removing ids in the selected array in the reverse order. You can confirm this by adding the following debug line in the checkMe function:

console.log('Checked state of checkbox id:' + id + ' is: ' + checkbox.prop('checked'));

Case1: Clicking checkAll when it is Unchecked; it calls checkMe() for each child checkbox but finds the 'checked' attribute as undefined. So it executes the delete code. After executing checkMe the 'checked' attribute is added on the checkbox.

Case2: Clicking checkAll when it is Checked; the checkMe() function finds the 'checked' attribute previously added and fills the array. Later an event is probably fired to remove the 'checked' attribute.

I changed the following lines to quickly test this and seems to be working:

Bind checkMe on change event instead of click in reload function:

$('.table_checkbox').bind('change', checkMe);

Change the condition for unchecked children in checkAll function when the .checkbox_all is checked:

if($(this).prop('checked') === false) {/*call child click*/}
//Use prop instead of attr because it takes care of 'undefined' cases as well. If you want to keep using attr because you're on an older version of jquery then add something like:
typeof $(this).attr('checked') == 'undefined'

and also the condition when .checkbox_all is unchecked:

if($(this).prop('checked') === true) {/*call child click*/}

Hope this helps. Here's a jsbin to play with..