jQuery how to undo a select change

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春和景丽
春和景丽 2020-12-02 14:13

I have a select box, and I\'d like to add a confirm before changing it to a specific option. Example:


                        
    
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  • 2020-12-02 14:49

    Oldschool way (before we used jquery):

    <select id="mySelect" onchange="if(confirm('Do you really want to change?')){ doSomething(); } else { this.selectedIndex=myIndex; }">
        <option value="foo" selected="selected">foo</option>
        <option value="bar">bar</option>
    </select>
    <script type="text/javascript">
        var myIndex = $('mySelect').selectedIndex;
    </script>
    
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  • 2020-12-02 14:53

    $(document).on('change','.change_response_status',function()
    {
        var responseStatusId = this.id;
        var responseID = $("#"+responseStatusId).attr('data-id');
        var previouesSatatus = $("#hidden_response_id_"+responseID).val();
        var confirmstatus = confirm("Are you sure you want to change status for this item?");
        var currentSelectedValue = $(this).val();
    
        if(confirmstatus==true)
        {
            $("#hidden_response_id_"+responseID).val(currentSelectedValue);
        }
        else
        {
            $(this).val(previouesSatatus);
            $("#hidden_response_id_"+responseID).val(previouesSatatus);
            return false;
        }
        return false;
    });
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
    <select data-id="2" id="response_id_2" class="change_response_status" name="status">
        <option value="1">Accept</option>
        <option value="2" selected="selected">No Respond</option>
        <option value="3">Reject</option>
    </select>
    <input class="hidden_response_class" id="hidden_response_id_2" type="hidden" value="1" name="hidden_response_staus">

    This is best way to display already selected option on click with using cancel on confirmation box.

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  • 2020-12-02 14:54

    If you are using Select2, you can use something below,

    $('select').on('select2:selecting', function() {
        if (!confirm('Are you sure you?')) {
             $(this).select2('close')
             return false
        }
    })
    
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  • 2020-12-02 14:59

    Rather than using a global variable (evil!) or a hidden element (abuse of the DOM) you can use the $.data feature:

    $('select').change(function() {
        var selected = $(this).val();
    
        if (selected == 'bar') {
            if (!confirm('Are you sure?')) {
                $(this).val($.data(this, 'current'));
                return false;
            }     
        }
    
        $.data(this, 'current', $(this).val());
    });
    
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  • 2020-12-02 15:00

    Here's a more verbose and commented version of lonesomeday's accepted answer that prompts for confirm on each change and uses .data() rather than jQuery.data().

    It might help people with understanding the logic a bit more.

    Accompanying jsFiddle is here.

    // set the initial data value
    $(document).ready(function() {
      var my_select = $("#my_select");
      my_select.data("current", "foo");
    });
    
    // when selecting another option
    $('select').change(function() {
      var $this = $(this);
      var selected = $this.val();
    
      logit($this, selected, 1); // log data to screen
    
      // if clicking cancel on the confirm dialog
      if (!confirm('Are you sure?')) {
        logit($this, selected, 2); // log data to screen
    
        // set the select's value to the stored data value
        var previous_data_value = $(this).data("current");
        $this.val(previous_data_value);
        // escape the onchange function 
        return false;
      }
    
      // if clicking OK, update the data value to the chosen option
      logit($this, selected, 3); // log data to screen
    
      $this.data("current", $this.val());
    
    });
    
    
    
    
    // helper functions only below
    
    $(document).on("click", ".clicker", function() {
      var my_select = $("#my_select");
      alert(my_select.data("current"));
    });
    
    
    function logit($this, selected, instance) {
      var current_data_value = $this.data("current");
      if (instance === 1) {
        var value_log = "<span>you selected the value: " + selected + "</span>";
        $(".container_2").append(value_log);
        var data_log = "<span>the previous value was: " + current_data_value + "</span>";
        $(".container_2").append(data_log);
      } else if (instance === 2) {
        $(".container_2").append("<span>you clicked Cancel, value was reverted to: " + current_data_value + "</span>");
    
      }
      if (instance === 3) {
        $(".container_2").append("<span>you clicked OK, value was changed from '" + current_data_value + "' to '" + selected + "'</span>");
      }
    
      $(".container_2").append("<span>------------------------------------------------------</span>");
    }
    * {
      box-sizing: border-box;
    }
    
    select {
      width: 200px;
      float: left;
    }
    
    .clicker {
      width: 200px;
      float: left;
    }
    
    .container_1 {
      margin: auto;
      width: 400px;
      background: lightgray;
      padding-top: 10px;
      padding-bottom: 10px;
    }
    
    .container_1:after {
      clear: both;
      content: " ";
      height: 0;
      display: block;
    }
    
    .container_2 {
      width: 400px;
      height: 300px;
      overflow-y: auto;
      border: 1px solid gray;
      padding: 10px;
      margin: auto;
      background: #222;
    }
    
    span {
      display: block;
      margin-bottom: 5px;
      color: lime;
      font-family: arial;
      font-size: 12px;
    }
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
    <div class="container_1">
    
      <select id="my_select">
    <option value="foo">foo</option>
    <option value="bar">bar</option>
    <option value="baz">baz</option>
    </select>
      <button class="clicker">what's the data value now?</button>
    </div>
    
    <div class="container_2">
    
    
    </div>

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