刷新页面后如何保持单个复选框处于选中状态?

问题描述：

HTML代码:

    <div class="wrap">
        <h3>Background Swap:</h3>
        <form action="" method="POST">
            <div id="checkbox-container">
                Shadowless background: <input type="checkbox" name="new_background" id="checker" <?php echo (isset($_POST['new_background']))? "checked='checked'": "";?>/><br /><br />
            </div>
            <input type="submit" name="submit" value="Upgrade Background" class="button" />
        </form>
    </div>

这将使复选框保持选中状态，但是当页面刷新或退出并返回时，将取消选中该复选框.因此，经过一些研究，我尝试了localStorage，但似乎还不太清楚.

This will make the checkbox stays checked, but when page is refresh or exit and comes back, the checkbox will be unchecked. Therefore, after some research, I tried the localStorage, but doesn't seem to quite figure it out yet.

localStorage代码:

localStorage code:

    var checkboxValue = JSON.parse(localStorage.getItem('checkboxValue')) || {};
    var $checkbox = $("#checkbox-container :checkbox");

    $checkbox.on("change", function(){
        $checkbox.each(function(){
            checkboxValue[this.id] = this.checked; 
        });
        localStorage.setItem("checkboxValue", JSON.stringify(checkboxValue));
    });

    //on page load
    $.each(checkboxValue, function(key, value){
        $("#" + key).prop('checked', value);
    });

我在localStorage代码周围有脚本标签，实现这些代码后，我的复选框仍然没有处于选中状态.

I have script tags around the localStorage code and after implementing these codes, my checkbox still doesn't stays checked.

两个代码都相同:

<div class="wrap">
<h3>Background Swap:</h3>
<form action="" method="POST">
    <div id="checkbox-container">
        Background Swap: <input type="checkbox" name="new_background"/>
    </div>
    <script>
        var checkboxValue = JSON.parse(localStorage.getItem('checkboxValue')) || {}
        var $checkbox = $("#checkbox-container :checkbox");

        $checkbox.on("change", function(){
            $checkbox.each(function(){
                checkboxValue[this.id] = this.checked; 
            });
            localStorage.setItem("checkboxValue", JSON.stringify(checkboxValue));
        });

        //on page load
        $.each(checkboxValue, function(key, value){
            $("#" + key).prop('checked', value);
        });
        </script>
        <input type="submit" name="submit" value="Upgrade Background" class="button"/>
</form>
</div>

我要感谢所有花时间帮助我解决问题的人，对@Pranav C Balan表示最大的感谢！！！查看完成的代码@ http://*.com/a/44321072/3037257

I would like to thank everyone that took time to help me figure out the solution to my question with the biggest thanks to @Pranav C Balan!!! Check out the finished code @ http://*.com/a/44321072/3037257

答

我认为您的代码是在加载表单元素之前执行的，因此请将其放在代码的末尾或使用之前，则不会选择任何内容，因为它尚未加载到DOM中.

I think your code is executing before the form elements are loading, so place it at the end of your code or wrap it using document ready handler to execute only after the elements are loaded. If you were placed the code before the element $("#checkbox-container :checkbox") would select nothing since it is not yet loaded in the DOM.

还有一件要做的事情，在您的代码中，该复选框没有任何 id ，因此，由于JSON是使用id值生成的，因此在元素中添加唯一的id以使其起作用.

One more thing to do, in your code the checkbox doesn't have any id so add a unique id to the element to make it work since the JSON is generating using the id value.

<div class="wrap">
  <h3>Background Swap:</h3>
  <form action="" method="POST">
    <div id="checkbox-container">
      Background Swap: <input type="checkbox" id="name" name="new_background" />
    </div>

    <input type="submit" name="submit" value="Upgrade Background" class="button" />
  </form>
  <script>
    var checkboxValue = JSON.parse(localStorage.getItem('checkboxValue')) || {}
    var $checkbox = $("#checkbox-container :checkbox");

    $checkbox.on("change", function() {
      $checkbox.each(function() {
        checkboxValue[this.id] = this.checked;
      });
      localStorage.setItem("checkboxValue", JSON.stringify(checkboxValue));
    });

    //on page load
    $.each(checkboxValue, function(key, value) {
      $("#" + key).prop('checked', value);
    });
  </script>
</div>

正在运行的演示: FIDDLE

<script>
  // document ready handler
  // or $(document).ready(Function(){...
  jQuery(function($) {
    var checkboxValue = JSON.parse(localStorage.getItem('checkboxValue')) || {}
    var $checkbox = $("#checkbox-container :checkbox");

    $checkbox.on("change", function() {
      $checkbox.each(function() {
        checkboxValue[this.id] = this.checked;
      });
      localStorage.setItem("checkboxValue", JSON.stringify(checkboxValue));
    });

    //on page load
    $.each(checkboxValue, function(key, value) {
      $("#" + key).prop('checked', value);
    });
  });
</script>
<div class="wrap">
  <h3>Background Swap:</h3>
  <form action="" method="POST">
    <div id="checkbox-container">
      Background Swap: <input type="checkbox" id="name" name="new_background" />
    </div>

    <input type="submit" name="submit" value="Upgrade Background" class="button" />
  </form>

</div>

正在运行的演示: FIDDLE

刷新页面后如何保持单个复选框处于选中状态?

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