jQuery中的onchange問​​題

Question

我正在創建選擇框，並且我爲jquery.it中的選擇框編寫了更改函數。但我的問題是，當我在選擇框中移動光標選項時，沒有選擇任何選項，我點擊了選擇框旁邊。但改變功能調用我不知道如何解決這個問題我的代碼被賦予波紋管

和我的小提琴被http://jsfiddle.net/6mhed8yL/

<select name="selecting" id="selecting" > 
    <option selected="selected" >--Control--</option> 
    <option id="Select All ">Select All</option> 
    <option id="Remove All " >Remove All</option> 
    <option id="Sample Questions" >Sample Questions</option> 
    <option id=" User Added Questions">User Added Questions</option> 
    <option id="Show All Questions" >Show All Questions</option> 
       </select> 

jQuery的

$('#selecting').change(function(){ 
     alert("check"); 
     var opt=$('#selecting').val(); 
     var url=""; 
     alert("option is"+opt); 
     // $("#selecting option:selected").removeAttr('disabled'); 
      //$("#selecting option:disabled").val(opt); 
      //$("#selecting option[value=" + opt + "]").attr('disabled', 'disabled'); 


     if(opt=="Select All") 
      { 
      $('input:checkbox').prop('checked', true); 
      $("select option:contains('Select All')").attr("disabled","disabled"); 
      $("select option:contains('Remove All')").removeAttr("disabled"); 
      $("select option:contains('Sample Questions')").removeAttr("disabled"); 
      $("select option:contains('User Added Questions')").removeAttr("disabled"); 
      $("select option:contains('Show All Questions')").removeAttr("disabled"); 


      } 
     else if(opt=="Remove All") 
      { 
      $("input:checkbox").prop("checked", false); 
      $("select option:contains('Remove All')").attr("disabled","disabled"); 
      $("select option:contains('Select All')").removeAttr("disabled"); 
      $("select option:contains('Sample Questions')").removeAttr("disabled"); 
      $("select option:contains('User Added Questions')").removeAttr("disabled"); 
      $("select option:contains('Show All Questions')").removeAttr("disabled"); 
      } 
     else if(opt=="Sample Questions") 
      { 

      $("select option:contains('Sample Questions')").attr("disabled","disabled"); 
      $("select option:contains('Select All')").removeAttr("disabled"); 
      $("select option:contains('Remove All')").removeAttr("disabled"); 
      $("select option:contains('User Added Questions')").removeAttr("disabled"); 
      $("select option:contains('Show All Questions')").removeAttr("disabled"); 
      url = "SampleQuestions.jsp"; 
      alert("sample"); 

      /* if (window.XMLHttpRequest) 
        req = new XMLHttpRequest(); 
        else if (window.ActiveXObject) 
        req = new ActiveXObject("Microsoft.XMLHTTP"); 
        req.open("GET", url, true); 

        req.onreadystatechange =callback; 

        req.send(null); */ 



      } 
     else if(opt=="User Added Questions") 
     { 
      $("select option:contains('User Added Questions')").attr("disabled","disabled"); 
      $("select option:contains('Select All')").removeAttr("disabled"); 
      $("select option:contains('Remove All')").removeAttr("disabled"); 
      $("select option:contains('Sample Questions')").removeAttr("disabled"); 
      $("select option:contains('Show All Questions')").removeAttr("disabled"); 
      $("select option:contains('Show All Questions')").removeAttr("disabled"); 

      url="UserAddedQuestion.jsp"; 
      alert("user"); 

     /* if (window.XMLHttpRequest) 
        req = new XMLHttpRequest(); 
        else if (window.ActiveXObject) 
        req = new ActiveXObject("Microsoft.XMLHTTP"); 
        req.open("GET", url, true); 

        req.onreadystatechange =callback; 

        req.send(null); 
        */ 

     } 
     else if(opt=="Show All Questions") 
      { 

      $("select option:contains('Show All Questions')").attr("disabled","disabled"); 
      $("select option:contains('Select All')").removeAttr("disabled"); 
      $("select option:contains('Remove All')").removeAttr("disabled"); 
      $("select option:contains('Sample Questions')").removeAttr("disabled"); 
      $("select option:contains('User Added Questions')").removeAttr("disabled"); 
      url="ShowAllQuestions.jsp"; 
      alert("all"); 

      /* if (window.XMLHttpRequest) 
        req = new XMLHttpRequest(); 
        else if (window.ActiveXObject) 
        req = new ActiveXObject("Microsoft.XMLHTTP"); 
        req.open("GET", url, true); 

        req.onreadystatechange =callback; 

        req.send(null); 
        */ 

      } 



    }); 

Answer 1

我已經更新的jsfiddle現在的工作。這裏[fiddle][1]http://jsfiddle.net/6mhed8yL/1/