如何限制下拉列表更改而不禁用它

Question

如何限制下拉列表選項更改而不禁用該下拉列表。
表示我無法更改該選項，並且該下拉列表不應該是隻讀的。
我的問題是我的服務器沒有閱讀障礙元素

Answer 1

Here's my bid

jQuery的

var lastSel = $('#foo').val(); 
$('#foo').change(function(){ 
    var $select = $(this), $status = $('#status'); 

    var $selOpt = $select.find('option:selected'); 
    if (!$selOpt.hasClass('disabled')){ 
     lastSel = $selOpt.index(); 
     $status.text('Selection changed to ' + $selOpt.val() + ' [' + lastSel + ']'); 
    }else{ 
     $selOpt.removeAttr('selected'); 
     $select.find('option:eq('+lastSel+')').attr('selected',true); 
     $status.text('Invalid selection, reverting to ' + lastSel); 
    } 
}); 

HTML

<select id="foo"> 
    <option value="">Please select one</option> 
    <option value="a">Option A</option> 
    <option value="b">Option B</option> 
    <option value="c" class="disabled">Option C</option> 
    <option value="d">Option D</option> 
    <option value="e">Option E</option> 
    <option value="f" class="disabled">Option F</option> 
    <option value="g">Option G</option> 
    <option value="h">Option H</option> 
    <option value="i" class="disabled">Option I</option> 
</select> 
<p id="status"></p> 

---

插件版本

(function($){ 
    $.fn.extend({ 
     restrictedSelect: function(disabledClass){ 
      disabledClass = disabledClass || 'disabled'; 

      return this.each(function(i,e){ 
       var $s = $(e); 

       // store the current selection. This is also used as a fall-back 
       // value when the user selects something invalid. 
       $s.data('currentSelection',$s.find('option:selected').index()); 

       $s.change(function(){ 
        var $cs = $s.find('option:selected'); 
        if ($cs.hasClass(disabledClass)){ 
         $cs.removeAttr('selected'); 
         $s.find('option:eq('+$s.data('currentSelection')+')').attr('selected',true); 
        }else{ 
         $s.data('currentSelection',$cs.index()); 
        } 
       }); 
      }); 
     } 
    }); 
})(jQuery); 

$('select').restrictedSelect('invalid-select-option'); 

Answer 2

$('#my_select').change(function(event){ 
    $(this).val(this.defaultSelected); 
}); 

Answer 3

你可以這樣做：

//save the value selected when you load the page 
var default = $('#yourselect option:selected').val(); 
//reset the value when the select change 
$('#yourselect').change(function(event){ 
    $(this).val(default); 
}); 

Answer 4

試試這個

<select id="selectId" data-default="1"> 
<option value="0">0</option> 
<option value="1">1</option> 
... 
</select> 

$('#selectId').change(function(){ 
    $(this).val($(this).data("default")); 
});