jquery动态添加以及遍历option并获取特定样式名称的option方法

<pre name="code" class="html"><script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script> <select class="form-control" id='selectId'> <option class="all" value="0">全部</option> <option class="all" value="1">os2</option> <option>os2-anthonos</option> <option>os2-apps</option> <option>os2-centralpoint</option> <option>kf5-experimental</option> </select> <script>  //动态添加option  //$("#selectId").append("<option value='"+value+"'>"+text+"</option>");  $(document).ready(function(){  var string = "";  $("#selectId option").each(function(){ //遍历全部option  var text = $(this).text(); //获取option的text  var value = $(this).val(); //获取option的value  if($(this).attr("class")=="all")   string +="{"+text+":"+value+"}";  });  alert(string.substring(0,string.length)); }); </script>