详解bootstrap用dropdown-menu实现上下文菜单

<div id="settingInGraph"> 
              <ul class="dropdown-menu" role="menu" 
                aria-labelledby="dropdownMenu" id="contextMenu"> 
                <li><a tabindex="-1" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >任务指派</a></li> 
                <li><a tabindex="-1" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >任务监听</a></li> 
                <li><a tabindex="-1" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >任务表单</a></li> 
                <li class="divider"></li> 
                <li><a tabindex="-1" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >...</a></li> 
              </ul> 
            </div> 

$("#settingInGraph").mousedown(function(e) { 
if (3 == e.which) { 
     document.oncontextmenu = function() {return false;} 
     $("#contextMenu").hide(); 
     $("#contextMenu").attr("style","display: block; position: fixed; top:" 
     + e.pageY 
     + "px; left:" 
     + e.pageX 
     + "px; width: 180px;"); 
     $("#contextMenu").show(); 
     } 
}); 
$("#settingInGraph").click(function(e) { 
$("#contextMenu").hide();              });