jQuery 如何限制选中复选框的数量？

How to limit the number of selected checkboxes?

提问by alexchenco

I have the following HTML:

我有以下 HTML：

<div class="pricing-levels-3">
  <p><strong>Which level would you like? (Select 3 Levels)</strong></p>
  <input class="single-checkbox"type="checkbox" name="vehicle" value="Bike">Level 1<br>
  <input class="single-checkbox" type="checkbox" name="vehicle" value="Bike">Level 2<br>
  <input class="single-checkbox" type="checkbox" name="vehicle" value="Bike">Level 3<br>
  <input class="single-checkbox" type="checkbox" name="vehicle" value="Bike">Level 4<br>
  <input class="single-checkbox" type="checkbox" name="vehicle" value="Bike">Level 5<br>
  <input class="single-checkbox" type="checkbox" name="vehicle" value="Bike">Level 6<br>
  <input class="single-checkbox" type="checkbox" name="vehicle" value="Bike">Level 7<br>
</div>

Live site:

直播网站：

http://www.chineselearnonline.com/amember/signup20.php

http://www.chineselearnonline.com/amember/signup20.php

How can I do it so that the user can only select 3 of those checkboxes?

我该怎么做才能让用户只能选择其中的 3 个复选框？

回答by letiagoalves

Using changeevent you can do something like this:

使用change事件你可以做这样的事情：

var limit = 3;
$('input.single-checkbox').on('change', function(evt) {
   if($(this).siblings(':checked').length >= limit) {
       this.checked = false;
   }
});

See this working demo

看到这个工作演示

回答by Praveen

Try like this.

像这样尝试。

On change event,

在更改事件中，

$('input[type=checkbox]').on('change', function (e) {
    if ($('input[type=checkbox]:checked').length > 3) {
        $(this).prop('checked', false);
        alert("allowed only 3");
    }
});

Check this in JSFiddle

在JSFiddle 中检查这个

回答by coder

Try this DEMO:

试试这个演示：

 $(document).ready(function () {
   $("input[name='vehicle']").change(function () {
      var maxAllowed = 3;
      var cnt = $("input[name='vehicle']:checked").length;
      if (cnt > maxAllowed) 
      {
         $(this).prop("checked", "");
         alert('Select maximum ' + maxAllowed + ' Levels!');
     }
  });
});

回答by Hammad Hassan

I think we should use clickinstead change

我认为我们应该click改用change

Working DEMO

工作演示

回答by entrop

$("input:checkbox").click(function(){
    if ($("input:checkbox:checked").length > 3){
      return false;
   }
});

回答by Jinhyeok Lee

$('.checkbox').click(function(){
  if ($('.checkbox:checked').length >= 3) {
    $(".checkbox").not(":checked").attr("disabled",true);
  }
  else 
    $(".checkbox").not(":checked").removeAttr('disabled');
});

i used this.

我用过这个。

回答by bzim

I'd say like letiagoalves said, but you might have more than one checkbox question in your form, so I'd recommend to do like this:

我会说就像 letiagoalves 所说的那样，但是您的表单中可能有多个复选框问题，因此我建议您这样做：

  var limit = 3;
    $('input.single-checkbox').on('change', function(evt) {
        if($('input.single-checkbox').siblings('input.single-checkbox:checked').length > limit) {
            this.checked = false;
        }
    });

回答by SarathSprakash

Working DEMO

工作演示

Try this

尝试这个

var theCheckboxes = $(".pricing-levels-3 input[type='checkbox']");
theCheckboxes.click(function()
{
    if (theCheckboxes.filter(":checked").length > 3)
        $(this).removeAttr("checked");
});

回答by Bobz

This is how I made it work:

这就是我让它工作的方式：

// Function to check and disable checkbox
function limit_checked( element, size ) {
  var bol = $( element + ':checked').length >= size;
  $(element).not(':checked').attr('disabled',bol);
}

// List of checkbox groups to check
var check_elements = [
  { id: '.group1 input[type=checkbox]', size: 2 },
  { id: '.group2 input[type=checkbox]', size: 3 },
];

// Run function for each group in list
$(check_elements).each( function(index, element) {
  // Limit checked on window load
  $(window).load( function() {
    limit_checked( element.id, element.size );
  })

  // Limit checked on click
  $(element.id).click(function() {
    limit_checked( element.id, element.size );
  });
});

回答by Vaimeo

I have Alter this function to auto uncheck previous

我有更改此功能以自动取消选中以前的

      var limit = 3;
      $('.compare_items').on('click', function(evt) {
        index = $(this).parent('td').parent('tr').index();
        if ($('.compare_items:checked').length >= limit) {
          $('.compare_items').eq(localStorage.getItem('last-checked-item')).removeAttr('checked');
          //this.checked = false;
        }
        localStorage.setItem('last-checked-item', index);
      });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="checkbox" class="compare_items">1
<input type="checkbox" class="compare_items">2
<input type="checkbox" class="compare_items">3
<input type="checkbox" class="compare_items">4
<input type="checkbox" class="compare_items">5
<input type="checkbox" class="compare_items">6
<input type="checkbox" class="compare_items">7
<input type="checkbox" class="compare_items">8
<input type="checkbox" class="compare_items">9
<input type="checkbox" class="compare_items">10