我使用这个jQuery块，它将在提交时为每个未选中的复选框添加一个隐藏输入。它将保证您每次都为每个复选框提交一个值，而不会弄乱您的标记，并冒着忘记在稍后添加的复选框上执行此操作的风险。它也与您正在使用的任何后端堆栈(PHP、Ruby等)无关。

// Add an event listener on #form's submit action...
$("#form").submit(
    function() {

        // For each unchecked checkbox on the form...
        $(this).find($("input:checkbox:not(:checked)")).each(

            // Create a hidden field with the same name as the checkbox and a value of 0
            // You could just as easily use "off", "false", or whatever you want to get
            // when the checkbox is empty.
            function(index) {
                var input = $('<input />');
                input.attr('type', 'hidden');
                input.attr('name', $(this).attr("name")); // Same name as the checkbox
                input.attr('value', "0"); // or 'off', 'false', 'no', whatever

                // append it to the form the checkbox is in just as it's being submitted
                var form = $(this)[0].form;
                $(form).append(input);

            }   // end function inside each()
        );      // end each() argument list

        return true;    // Don't abort the form submit

    }   // end function inside submit()
);      // end submit() argument list

这是对之前答案的一种尝试，以自动保留具有特定值(在本例中为0)的未选中复选框，而不会在提交时选中所有复选框。

$("form").submit(function () {
    let this_master = $(this);

    // Remove any of the hidden values that may already be there (if the user previously canceled the submit)
    this_master.find("*[id^='hiddenchkinput_']").remove();

    // Get all unchecked checkboxes
    this_master.find('input:checkbox:not(:checked)').each(function () {
      let thisChk = $(this);

      // Create a hidden input with the same name as the checkbox
      let newInput = document.createElement('input');
      $(newInput).attr('name', thisChk.attr('id'))
        .attr('id', 'hiddenchkinput_' + thisChk.attr('id'))
        .attr('type', 'hidden')
        .val('0');
      // Append the new input to the end of the form
      this_master.append(newInput);
    });
})

I see this question is old and has so many answers, but I'll give my penny anyway. My vote is for the javascript solution on the form's 'submit' event, as some has pointed out. No doubling the inputs (especially if you have long names and attributes with php code mixed with html), no server side bother (that would require to know all field names and to check them down one by one), just fetch all the unchecked items, assign them a 0 value (or whatever you need to indicate a 'not checked' status) and then change their attribute 'checked' to true

    $('form').submit(function(e){
    var b = $("input:checkbox:not(:checked)");
    $(b).each(function () {
        $(this).val(0); //Set whatever value you need for 'not checked'
        $(this).attr("checked", true);
    });
    return true;
});

这样你会得到一个像这样的$_POST数组:

Array
(
            [field1] => 1
            [field2] => 0
)

这个解决方案的灵感来自@desw的一个。

如果您的输入名称是“表单样式”的，那么只要选中一个复选框，您就会失去与复选框值的数组索引关联，每次选中一个复选框，这种“分离”就增加一个单元。这可能是用于插入由某些字段组成的雇员的表单的情况，例如:

<input type="text" name="employee[]" />
<input type="hidden" name="isSingle[] value="no" />
<input type="checkbox" name="isSingle[] value="yes" />

如果您一次插入三个员工，并且第一个和第二个员工是单个的，那么您最终将得到一个5元素的isSingle数组，因此您将不能一次遍历三个数组，例如，为了在数据库中插入员工。

你可以用一些简单的数组后处理来克服这个问题。我在服务器端使用PHP，我这样做:

$j = 0;
$areSingles = $_POST['isSingle'];
foreach($areSingles as $isSingle){
  if($isSingle=='yes'){
    unset($areSingles[$j-1]);
  }
  $j++;
}
$areSingles = array_values($areSingles);

有一个更好的解决办法。 首先，只向选中的复选框提供name属性。 然后点击提交，通过JavaScript函数检查所有未选中的框。 当你提交时，只有那些会在表单集合中检索到那些有name属性的。

  //removing name attribute from all checked checkboxes
                  var a = $('input:checkbox:checked');
                   $(a).each(function () {
                       $(this).removeAttr("name");        
                   });

   // checking all unchecked checkboxes
                   var b = $("input:checkbox:not(:checked)");
                   $(b).each(function () {
                       $(this).attr("checked", true);
                   });

优势: 不需要创建额外的隐藏框，并操作它们。

Checkboxes usually represent binary data that are stored in database as Yes/No, Y/N or 1/0 values. HTML checkboxes do have bad nature to send value to server only if checkbox is checked! That means that server script on other site must know in advance what are all possible checkboxes on web page in order to be able to store positive (checked) or negative (unchecked) values. Actually only negative values are problem (when user unchecks previously (pre)checked value - how can server know this when nothing is sent if it does not know in advance that this name should be sent). If you have a server side script which dynamically creates UPDATE script there's a problem because you don't know what all checkboxes should be received in order to set Y value for checked and N value for unchecked (not received) ones.

由于我在数据库中存储值“Y”和“N”，并通过页面上的选中和未选中复选框表示它们，我为每个值(复选框)添加了“Y”和“N”值的隐藏字段，然后使用复选框进行可视化表示，并使用简单的JavaScript函数check()来根据选择设置if的值。

<input type="hidden" id="N1" name="N1" value="Y" />
<input type="checkbox"<?php if($N1==='Y') echo ' checked="checked"'; ?> onclick="check(this);" />
<label for="N1">Checkbox #1</label>

使用一个JavaScript onclick监听器和调用函数check()在我的网页上的每个复选框:

function check(me)
{
  if(me.checked)
  {
    me.previousSibling.previousSibling.value='Y';
  }
  else
  {
    me.previousSibling.previousSibling.value='N';
  }
}

这样，“Y”或“N”值总是发送到服务器端脚本，它知道什么是应该更新的字段，没有必要将复选框“上”值转换为“Y”或未接收复选框转换为“N”。

注意:空格或新行也是兄弟姐妹，所以这里我需要。previoussibling . previoussibling .value。如果没有空格，则只有.previousSibling.value

你不需要像以前那样显式地添加onclick监听器，你可以使用jQuery库动态添加点击监听器函数来更改页面中所有复选框的值:

$('input[type=checkbox]').click(function()
{
  if(this.checked)
  {
    $(this).prev().val('Y');
  }
  else
  {
    $(this).prev().val('N');
  }
});