引導，選擇和鍵盤導航

Question

我使用的自舉選https://silviomoreto.github.io/bootstrap-select/

和我有圖片網址作爲值以下的下拉菜單。

當我使用我的鼠標並選擇每個選項時，一切正常。但是，當我使用鍵盤的上下箭頭並突出顯示每個選項時，我想要一個事件觸發，以便可以翻轉可用的圖像預覽。 （此處未顯示）當我使用鼠標單擊突出顯示的選項時，它會按預期方式顯示所選圖像的預覽。

問題是我該如何實現它，以便用戶通過鍵盤箭頭上下移動選擇的值，以便他們可以輕鬆地翻轉思考可用圖像，而不會每次都敲擊輸入。我曾嘗試以下

$('.selectpicker').on('changed.bs.select', function (e, clickedIndex, newValue, oldValue) { 
    var selected = $(e.currentTarget).val(); 
    alert(selected); 
}); 
but this only works after I hit enter. Any suggestions. 


    <select class="selectpicker form-control" data-size="10" name="cboImage" id="cboImage" onchange="cboImage_onChange()" size="1" tabindex="-98"> 

    <option value="images/1x1.gif">[BLANK IMAGE]</option> 
    <option value="upload/33/img_3009.jpg">10-16-2015 11-56-30 AM.jpg</option> 
    <option value="upload/00/img_3031.jpg">10478631_1494051514186448_2207392604969581462_o.jpg</option> 
    <option value="upload/BB/img_3003.jpg" selected="">10920935_1385769295058553_7186298008992739460_n.jpg</option> 
    <option value="upload/22/img_3006.jpg">11-29-2014 6-35-20 PM.jpg</option> 
    <option value="upload/22/img_3004.jpg">11025665_1380482578935990_5955532852167626303_n.jpg</option> 
    <option value="upload/77/img_2913.jpg">12339668_1517870915178926_9132688390289736139_o.jpg</option> 
    <option value="upload/EE/img_2972.jpg">269586_10151304206069257_1562006627_n.png</option> 
    <option value="upload/88/img_3005.jpg">3305476.jpg</option> 

<option value="upload/00/img_3008.jpg">536962_1.jpg</option> 
<option value="upload/FF/img_2969.jpg">9-3-2015 9-03-19 AM.jpg</option> 
<option value="upload/77/img_2971.jpg">analyze_image.jpg</option> 
<option value="upload/AA/img_3007.jpg">Copy of FL-SAR00_226876_1.jpg</option> 
<option value="upload/11/img_2914.jpg">holiday2015_1_image.jpg</option> 
<option value="upload/33/img_3015.jpg">IMAG0002.jpg</option> 
<option value="upload/BB/img_3013.jpg">IMAG0002.jpg</option> 
<option value="upload/55/img_3014.jpg">IMAG0003.jpg</option> 
<option value="upload/BB/img_3016.jpg">IMAG0003.jpg</option> 
<option value="upload/66/img_3017.jpg">IMAG0004.jpg</option> 
<option value="upload/CC/img_3012.jpg">IMAG0004.jpg</option> 
<option value="upload/66/img_3019.jpg">IMAG0023.jpg</option> 
<option value="upload/FF/img_3018.jpg">IMAG0053.jpg</option> 
<option value="upload/88/img_3011.jpg">image119037-180ae8ff18269a6e395200cb831d928e.jpg</option> 
<option value="upload/66/img_3029.jpg">IMG_1113.JPG</option> 
<option value="upload/CC/img_3028.jpg">IMG_1114.JPG</option> 
<option value="upload/FF/img_3027.jpg">IMG_1123.JPG</option> 
<option value="upload/BB/img_3030.jpg">IMG_1125.JPG</option> 
<option value="upload/AA/img_2917.jpg">L7ViI0Pm_400x400.png</option> 
<option value="upload/CC/img_3025.jpg">MuscleMadison11yrs.jpg</option> 
<option value="upload/FF/img_2960.jpg">My Image</option> 
<option value="upload/BB/img_3026.jpg">TimesSquare2013.jpg</option> 
<option value="upload/99/img_3010.jpg">Windsor-at-Lakoya-Front-Elevation-1024x656.jpg</option> 

      </select> 

Answer 1

爲了使用密鑰UP/DOWN鍵選擇你需要附上keydown事件的處理程序$元素（「div.dropdown-menu.open禮」）。

要選擇你需要使用的元素：

$('.selectpicker').selectpicker('val', selVal); 

所以片段是：

$(function() { 
 
    $('.selectpicker').selectpicker({ 
 
    style: 'btn-info', 
 
    size: 4 
 
    }); 
 
    $('div.dropdown-menu.open li').on('keydown', function (e) { 
 
    if (e.keyCode == 38) { // Up 
 
     var previousEle = $(this).prev(); 
 
     if (previousEle.length == 0) { 
 
     previousEle = $(this).nextAll().last(); 
 
     } 
 
     var selVal = $('.selectpicker option').filter(function() { 
 
     return $(this).text() == previousEle.text(); 
 
     }).val(); 
 
     $('.selectpicker').selectpicker('val', selVal); 
 

 
     return; 
 
    } 
 
    if (e.keyCode == 40) { // Down 
 
     var nextEle = $(this).next(); 
 
     if (nextEle.length == 0) { 
 
     nextEle = $(this).prevAll().last(); 
 
     } 
 
     var selVal = $('.selectpicker option').filter(function() { 
 
     return $(this).text() == nextEle.text(); 
 
     }).val(); 
 
     $('.selectpicker').selectpicker('val', selVal); 
 

 
     return; 
 
    } 
 
    }); 
 
});

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css"> 
 
<link rel="stylesheet" 
 
     href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.10.0/css/bootstrap-select.min.css"> 
 
<script src="https://code.jquery.com/jquery-1.12.1.min.js"></script> 
 
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script> 
 
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.10.0/js/bootstrap-select.min.js"></script> 
 

 
<select class="selectpicker form-control" data-size="10" name="cboImage" id="cboImage" size="1" tabindex="-98"> 
 
    <option value="images/1x1.gif">[BLANK IMAGE]</option> 
 
    <option value="upload/33/img_3009.jpg">10-16-2015 11-56-30 AM.jpg</option> 
 
    <option value="upload/00/img_3031.jpg">10478631_1494051514186448_2207392604969581462_o.jpg</option> 
 
    <option value="upload/BB/img_3003.jpg" selected="">10920935_1385769295058553_7186298008992739460_n.jpg</option> 
 
    <option value="upload/22/img_3006.jpg">11-29-2014 6-35-20 PM.jpg</option> 
 
    <option value="upload/22/img_3004.jpg">11025665_1380482578935990_5955532852167626303_n.jpg</option> 
 
    <option value="upload/77/img_2913.jpg">12339668_1517870915178926_9132688390289736139_o.jpg</option> 
 
    <option value="upload/EE/img_2972.jpg">269586_10151304206069257_1562006627_n.png</option> 
 
    <option value="upload/88/img_3005.jpg">3305476.jpg</option> 
 
    <option value="upload/00/img_3008.jpg">536962_1.jpg</option> 
 
    <option value="upload/FF/img_2969.jpg">9-3-2015 9-03-19 AM.jpg</option> 
 
    <option value="upload/77/img_2971.jpg">analyze_image.jpg</option> 
 
    <option value="upload/AA/img_3007.jpg">Copy of FL-SAR00_226876_1.jpg</option> 
 
    <option value="upload/11/img_2914.jpg">holiday2015_1_image.jpg</option> 
 
    <option value="upload/33/img_3015.jpg">IMAG0002.jpg</option> 
 
    <option value="upload/BB/img_3013.jpg">IMAG0002.jpg</option> 
 
    <option value="upload/55/img_3014.jpg">IMAG0003.jpg</option> 
 
    <option value="upload/BB/img_3016.jpg">IMAG0003.jpg</option> 
 
    <option value="upload/66/img_3017.jpg">IMAG0004.jpg</option> 
 
    <option value="upload/CC/img_3012.jpg">IMAG0004.jpg</option> 
 
    <option value="upload/66/img_3019.jpg">IMAG0023.jpg</option> 
 
    <option value="upload/FF/img_3018.jpg">IMAG0053.jpg</option> 
 
    <option value="upload/88/img_3011.jpg">image119037-180ae8ff18269a6e395200cb831d928e.jpg</option> 
 
    <option value="upload/66/img_3029.jpg">IMG_1113.JPG</option> 
 
    <option value="upload/CC/img_3028.jpg">IMG_1114.JPG</option> 
 
    <option value="upload/FF/img_3027.jpg">IMG_1123.JPG</option> 
 
    <option value="upload/BB/img_3030.jpg">IMG_1125.JPG</option> 
 
    <option value="upload/AA/img_2917.jpg">L7ViI0Pm_400x400.png</option> 
 
    <option value="upload/CC/img_3025.jpg">MuscleMadison11yrs.jpg</option> 
 
    <option value="upload/FF/img_2960.jpg">My Image</option> 
 
    <option value="upload/BB/img_3026.jpg">TimesSquare2013.jpg</option> 
 
    <option value="upload/99/img_3010.jpg">Windsor-at-Lakoya-Front-Elevation-1024x656.jpg</option> 
 
</select>