javascript - 计算用户使用 OnClick() 放入 HTML 表中的数字的平均值

Question

目前在识别我的 HTML/JavaScript 代码中的错误时遇到问题，该错误阻止我的 JavaScript 函数计算表格用户输入的五个数字的平均值。

当我在所需的单元格中输入数字后单击“计算成绩”时，没有任何反应。努力看到问题。

var table = document.getElementById("myTable");
var rows = table.rows;
for (var i = 0; i < rows.length; i++) {
  var cells = rows[i].cells;
  var sum = 0;
  for (var x = 0; x < cells.length; x++) {
    var cell = cells[x];
    sum += parseInt(cell.innerHTML);
  }
  var average = sum / cells.length;
  rows[i].innerHTML += "<td>" + average + "</td>";
}

<table id="myTable" style="width:100%">
  <tr>
    <th id="StudentName" bgcolor="FFF55A">Name</th>
    <th id="IDnumber" bgcolor="#FFF55A">ID</th>
    <th bgcolor="#FFF55A">Assignment 1</th>
    <th bgcolor="#FFF55A">Assignment 2</th>
    <th bgcolor="#FFF55A">Assignment 3</th>
    <th bgcolor="#FFF55A">Assignment 4</th>
    <th bgcolor="#FFF55A">Assignment 5</th>
    <th bgcolor="#FFF55A">Final</th>
  </tr>
  <tr>
    <td contenteditable='false'>Person1 </td>
    <td>1546396</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'>Person2</td>
    <td contenteditable='false'>45942544</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'>Person3</td>
    <td contenteditable='false'>48498465</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'> Person4</td>
    <td contenteditable='false'>4964984</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'>Person5</td>
    <td contenteditable='false'> 5686846</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'>Person6</td>
    <td contenteditable='false'>498465</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'>Person7</td>
    <td contenteditable='false'>654684</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'>Person8</td>
    <td contenteditable='false'>6498497</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
  <tr>
    <td contenteditable='false'>Person9</td>
    <td contenteditable='false'>8749846</td>
    <td contenteditable='true'>2</td>
    <td contenteditable='true'>45</td>
    <td contenteditable='true'>57</td>
    <td contenteditable='true'>2</td>
    <td contenteditable='true'>4</td>
  </tr>
  <tr>
    <td contenteditable='false'>Person10</td>
    <td contenteditable='false'>984894</td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
    <td contenteditable='true'></td>
  </tr>
</table>
<button onclick="myFunction()" class="button1">Calculate grade</button>

Answer 1

我稍微编辑了一下你的 fiddle :https://jsfiddle.net/StarStep/m7v1j5zz/105/并在计算按钮上添加了一个事件监听器: <button id="myFunction" class="button1">Calculate grade</button>

function myFunction() {
   var table = document.getElementById("myTable");
   var rows = table.rows;

   for (var i = 1; i < rows.length; i++) {
     var cells = rows[i].cells;
     var sum = 0;
         var numbers = 0;
     for (var x = 2; x < (cells.length -1); x++) {
       var cell = cells[x];
       var addme = parseInt(cell.innerHTML);
       if(!isNaN(addme)) {       
          sum += addme;
          numbers++;
       }
     }
     var average = sum / numbers;
     rows[i].cells[7].innerHTML = "<td>" + Math.round(average) + "</td>";
   }
 }

document.getElementById('myFunction').onclick = myFunction;