<script type="text/javascript"> //鼠標按下時的X Y坐標 var mouseDownX; var mouseDownY; //鼠標按下時移動的X Y 坐標 var mouseMoveX; var mouseMoveY; //移動的狀態 var isMove = false; /*初始化 選擇框 */ function init() {  $("#selected").css("display", "none");  $("#selected").css("top", "0");  $("#selected").css("left", "0");  $("#selected").css("width", "0");  $("#selected").css("height", "0"); } $(document).ready(function() {  init();  var selectedTD = new Array();//創建被選中表格數組  var TD = $("td");//獲取所有表格信息  for ( var i = 0; i < TD.length; i++) {   selectedTD.push(TD[i]);  }  $("#tableDiv").mousedown(function(event) {   mouseDownX = event.clientX - $(this).offset().left;;   mouseDownY = event.clientY - $(this).offset().top;   console.log("mouseDownX=" + mouseDownX +" mouseDownY=" + mouseDownY );   if(event.target.id.match(/selected/)) {    isMove = true;   }   //鼠標按下并移動時進行判斷（拖拽 or 畫框）   $("#tableDiv").mousemove(function(event) {    mouseMoveX = event.clientX - $(this).offset().left;    mouseMoveY = event.clientY - $(this).offset().top;    var selectDiv = document.getElementById("selected");    if (isMove) {     //拖拽的代碼，因為實在不想算 xy 了，所以使用了jquery ui     $("#selected").draggable();     //這部分是負責畫框的時候，實時把框住的表格變色的，（代碼和下面的代碼重復了）     var left = selectDiv.offsetLeft, top = selectDiv.offsetTop; width = selectDiv.offsetWidth, height = selectDiv.offsetHeight;     for ( var i = 0; i < selectedTD.length; i++) {      var sl = selectedTD[i].offsetWidth + selectedTD[i].offsetLeft;      var st = selectedTD[i].offsetHeight + selectedTD[i].offsetTop;      if (sl > left && st > top && selectedTD[i].offsetLeft < left + width && selectedTD[i].offsetTop < top + height) {       if (selectedTD[i].className.indexOf("selected") == -1) {        selectedTD[i].className = "selected";       }      } else {        if (selectedTD[i].className.indexOf("selected") != -1) {         selectedTD[i].className = "TD";        }      }     }    } else {     //重復的代碼，完了再把它抽取出來     var left = selectDiv.offsetLeft, top = selectDiv.offsetTop; width = selectDiv.offsetWidth, height = selectDiv.offsetHeight;     for ( var i = 0; i < selectedTD.length; i++) {      var sl = selectedTD[i].offsetWidth + selectedTD[i].offsetLeft;      var st = selectedTD[i].offsetHeight + selectedTD[i].offsetTop;      if (sl > left && st > top && selectedTD[i].offsetLeft < left + width && selectedTD[i].offsetTop < top + height) {       if (selectedTD[i].className.indexOf("selected") == -1) {        selectedTD[i].className = "selected";       }      } else {       if (selectedTD[i].className.indexOf("selected") != -1) {         selectedTD[i].className = "TD";        }      }     }     //鼠標抬起結束畫框，和拖動     $("#tableDiv").mouseup(function() {      console.log("mouseUpX=" + mouseMoveX + " mouseUpY=" + mouseMoveX);      isMove = false;      $(this).unbind('mousemove');     })     //畫框     displaySelected(mouseDownY, mouseDownX, mouseMoveX, mouseMoveY);    }   })  })  //當鼠標在已經畫好的框上時，改變鼠標指針樣式，就是十字形了  $("#selected").mouseenter(function() {   $("#selected").css("cursor", "move");  }); }); function displaySelected(mouseDownY, mouseDownX, mouseUpX, mouseUpY) {  $("#selected").css("display", "block");  $("#selected").css("top", mouseDownY);  $("#selected").css("left", mouseDownX);  var moveX = mouseMoveX - mouseDownX;  var moveY = mouseMoveY - mouseDownY;  if (moveY < 0) {    $("#selected").css("top", event.clientY - $("#table").offset().top);  }  if (moveX < 0) {   $("#selected").css("left", event.clientX - $("#table").offset().left);  }  $("#selected").css("width", Math.abs(moveX));  $("#selected").css("height", Math.abs(moveY)); } </script>

<div id="tableDiv" style="width: 1500px; height: 1500px;top: 100px; left:100px; position: absolute;">  <div id="selected" style="border:5px dotted rgb(239, 37, 17);position: absolute;display: none;"></div>  <table border="1" style=" width: 1500px; height: 1500px;" id="table">  <tr>   <td id="1" class="TD"></td>   <td id="2" class="TD"></td>   <td id="3" class="TD"></td>   <td id="4" class="TD"></td>   <td id="5" class="TD"></td>   <td id="6" class="TD"></td>  </tr>  <tr>   <td id="7" class="TD"></td>   <td id="8" class="TD"></td>   <td id="9" class="TD"></td>   <td id="10" class="TD"></td>   <td id="11" class="TD"></td>   <td id="12" class="TD"></td>  </tr>  <tr>   <td id="1" class="TD"></td>   <td id="2" class="TD"></td>   <td id="3" class="TD"></td>   <td id="4" class="TD"></td>   <td id="5" class="TD"></td>   <td id="6" class="TD"></td>  </tr>  </table> <!--表格代碼太多所以...--> </div>