How to detect a checkbox click in jQuery

问题:

I cannot detect when and which checkbox gets clicked from script below:

HTML Snippet:

<label for="checkbox[1]"><input type="checkbox" name="checkbox[1]" id="checkbox[1]" class="detectThisChange" value="10.00" checked=""> Amount $10.00</label>
<label for="checkbox[2]"><input type="checkbox" name="checkbox[2]" id="checkbox[2]" class="detectThisChange" value="20.00" checked=""> Amount $20.00</label>
<label for="checkbox[3]"><input type="checkbox" name="checkbox[3]" id="checkbox[3]" class="detectThisChange" value="30.00" checked=""> Amount $30.00</label>

jQuery Snippet:

$(document).ready(function() {
  $(window).load(function() {
// ... //
        $('.detectThisChange').change(function(event){
          var targetID = triggerEvent.target.id; // get the id that triggered the event
          var posStart = targetID.indexOf('[') + 1;
          var posEnd = targetID.indexOf(']');
          var i = targetID.substring(posStart, posEnd); // get the index of the id that triggered the event

          if ( $('#checkbox\\['+ i +'\\]').prop('checked') != true ) {
            alert('checkbox ' + i + ' was checked');
          }
          else {
            alert('checkbox ' + i + ' was unchecked');
          }

        });
// ... //
  }); // end .load()
}); // end .ready()

Appended:

The problem I am experiencing is that none of my alerts work. So that tells me the change() function is not firing.

回答1:

If you are adding this HTML dinamically, you should use the .on() method, like:

$(document).on('change', '.detectThisChange', function() {
    // your code
});

Give it a try and let me know if it helps.

回答2:

Try like this

$("input[type=checkbox]").is(":checked") // returns boolean checked or unchecked

---

   var arr = [];
    $("input[type=checkbox]").each(function () {
        var self = $(this);
        if (self.is(':checked')) {
            arr.push(self.attr("id"));
        }
    });
    console.log(arr);

EdIted:

$("input[type=checkbox]").on('change', function () {
    var self = $(this);
    if (self.is(":checked")) {
        console.log("checkbox  id =" + self.attr("id") + "is checked ");
    } else {
        console.log("Id = " + self.attr("id") + "is Unchecked ");
    }
});

Edited 2 :

$("body").on('change','.detectThisChange', function () {
    var self = $(this);
    if (self.is(":checked")) {
        console.log("checkbox  id =" + self.attr("id") + "is checked ");
    } else {
        console.log("Id = " + self.attr("id") + "is Unchecked ");
    }
});

Working Demo

Learn jQuery: Simple and easy jQuery tutorials blog

回答3:

Try on change event with this id selector as 'input[id^=checkbox]':

$(function() {
  $('input[id^=checkbox]').on('change', function() {
    console.log(this.value, this.checked);
  }).trigger('change');//fire event on page load
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label for="checkbox[1]">
  <input type="checkbox" name="checkbox[1]" id="checkbox[1]" class="detectThisChange" value="10.00" checked="">Amount $10.00</label>
<label for="checkbox[2]">
  <input type="checkbox" name="checkbox[2]" id="checkbox[2]" class="detectThisChange" value="20.00" checked="">Amount $20.00</label>
<label for="checkbox[3]">
  <input type="checkbox" name="checkbox[3]" id="checkbox[3]" class="detectThisChange" value="30.00" checked="">Amount $30.00</label>

回答4:

Try this :

$(".detectThisChange").on('change', function () {

    alert("In the function");
    var targetID = this.id; // get the id that triggered the event
    var posStart = targetID.indexOf('[') + 1;
    var posEnd = targetID.indexOf(']');
    var i = targetID.substring(posStart, posEnd); // get the index of the id that triggered the event

    if ($('#checkbox\\[' + i + '\\]').prop('checked') == true) {
        alert('checkbox ' + i + ' was checked');
    } else {
        alert('checkbox ' + i + ' was unchecked');
    }
});

Here's the JSFiddle, even though you have an answer :)

回答5:

Try:)

if ( $('#checkbox\\['+ i +'\\]').is(":checked") ) {
  alert('checkbox ' + i + ' was checked');
}
else {
  alert('checkbox ' + i + ' was unchecked');
}