;(function($){ $.fn.extend({  "jLzindex" : function(){ //用于判斷和設置各個對話框的z-index  var $dragIndex = $(this);  var arrzIndex = new Array();  for(var i=0; i < $dragIndex.length; i++){ //初始化數組元素值，并按拖拽項順序設置z-index值   var zIdxNum = 10000 - i - i -2;   arrzIndex[i] = {"getId":"drag" + ($dragIndex.length - i),"zIdx":zIdxNum};   $("#drag" + ($dragIndex.length - i)).css("z-index",zIdxNum);  }  $dragIndex.mousedown(function(){   var i = 0;   var dIndex = 0;   while(arrzIndex[i]){ //找到當前點擊項在數組里的下標   if(arrzIndex[i].getId == $(this).attr("id")){ dIndex = i;}   i++;   }   for(var i = dIndex; i >=0; i--){ //把點擊項移至數組第一位，其他項后移   if(i > 0){    arrzIndex[i].getId = arrzIndex[i-1].getId;    $("#" + arrzIndex[i].getId).css("z-index",arrzIndex[i].zIdx);   } else{    arrzIndex[i].getId = $(this).attr("id");    $("#" + arrzIndex[i].getId).css("z-index",arrzIndex[i].zIdx);   }   }  });  },  "jLdraggable" : function(mod){ //拖拽插件  var model = mod;  var draggable = false;   var $drag = $(this);  $drag.find(".dragBar").mousedown(function(e){   draggable = true;   var mouseLeft = e.pageX - $drag.find(".dragBar").offset().left; //鼠標在拖拽區域中的橫向距離   var mouseTop = e.pageY - $drag.find(".dragBar").offset().top; //鼠標在拖拽區域中的橫向距離   if(model == "cFade"){ //原位置元素半透明   $drag.clone(false).appendTo("body").addClass("dragShadow").fadeTo(0,0.2).css("z-index",parseInt($drag.css("z-index")) - 1);   } else if(model == "dFade"){ //跟隨鼠標元素半透明   $drag.clone(false).appendTo("body").addClass("dragShadow").css("z-index",parseInt($drag.css("z-index")) - 1);   $drag.fadeTo(0,0.2);   }   $(document).mousemove(function(e){   if(draggable){    var winWidth = $(window).width();    var winHeight = $(window).height();    var dragLeft = e.pageX - mouseLeft;    var dragTop = e.pageY - mouseTop;        //拖拽框不能超出窗口邊界    if(dragLeft < 0){dragLeft = 0;}    if(dragLeft + $drag.width() > winWidth){    dragLeft = winWidth - $drag.width();    }    if(dragTop < 0){dragTop = 0;}    if(dragTop + $drag.height() > winHeight){    dragTop = winHeight - $drag.height();    }        $drag.css("left",dragLeft + "px");    $drag.css("top",dragTop + "px");   } else{    return false;   }   });  });  $(document).mouseup(function(){   draggable = false;   $(".dragShadow").remove();   if(model == "dFade"){   $drag.fadeTo(0,1);    }  });  } })})(jQuery)

<script type="text/javascript" src="js/jquery.min.js"></script> <script type="text/javascript" src="js/jquery.jLdraggable.js"></script> <script type="text/javascript">$(document).ready(function(){ $("#drag1").jLdraggable(); //無參數，沒有影子 $("#drag2").jLdraggable("cFade"); //cFade，定義原位置半透明陰影 $("#drag3").jLdraggable("dFade"); //dFade，定義跟隨鼠標的半透明陰影 $(".dragIndex").jLzindex(); //多個窗口的z-index處理});</script><style type="text/css">.dragTitle{ width:120px; height:27px; background:url(images/drag_01.jpg); cursor:move;}.dragContent{ width:120px; height:73px; background:url(images/drag_02.jpg); line-height:73px; text-align:center;}#drag1{ width:120px;  position:absolute;  left:10px;  top:10px;}#drag2{ width:120px;  position:absolute;  left:90px;  top:90px;}#drag3{ width:120px;  position:absolute;  left:170px;  top:170px;}</style><div id="drag1" class="dragIndex"> <div class="dragBar dragTitle"></div> <div class="dragContent">無參數</div></div><div id="drag2" class="dragIndex"> <div class="dragBar dragTitle"></div> <div class="dragContent">原位半透明</div></div><div id="drag3" class="dragIndex"> <div class="dragBar dragTitle"></div> <div class="dragContent">拖拽半透明</div></div>