Question

所以我一直试图制作一个扩展程序，根据assignmentScores div中的一堆值来计算某人的平均成绩。这些成绩来自一个名为PowerSchool的网站，每个成绩都没有ID，所以我有jquery搜索页面。

这是页面格式化的方式，但这只是一个等级：

<div class="box-round" id="assignmentScores" style="">
<h2>Assignment Scores</h2>
  <table border="0" cellpadding="0" cellspacing="0" align="center" width="99%">
    <tbody><tr>
      <th>Due Date</th>
      <th>Category</th>
      <th>Assignment</th>
      <th>Standard</th>
      <th class="center">Score</th>
      <th class="center"></th>
      <th class="center">Grd</th>
      <th class="center" colspan="5">Codes</th>
    </tr>

<tr class="oddRow">
<td>11/12/2015</td>
<td>Classwork</td>
<td>In Class Notes</td>
<td></td>
<td align="center">30/30</td>
<td align="center"></td>
<td align="center">A+</td>

这是我的代码：

$(document).ready(function() {
    var arr = [];
    var numerator = 0;
    var denominator = 0;
    i = 0;

    //add value of all elements in assignmentScores that are centered to arr (grades are the only centered thing)
    $('#assignmentScores').each(function()
        if(isNaN($(this).attr('td [align="center"]')){
            arr[i++] = $(this).attr('td [align="center"]');
        }
    );

    //for every item in the array, add up numerators and denominators
    for each(var item in numerator){
        numerator += arr[item].substring(0, arr[item].indexOf("/")-1);
        denominator += arr[item].substring(arr[item].indexOf("/")+1, arr[item].length);
    }

    //print out the grade in h1 of assignmentScores
    $('#assignmentScores h1').append(numerator/denominator);

});

我对Javascript很陌生，我已经把它放在JSFiddle中了，我不确定它在做什么，或者它甚至做了什么。

感谢。

Answer 1

是的，这是可能的，但它相当复杂。

Here's a working Fiddle

相关的jQuery代码：

// We're going to do a lot of work, so let's get table in a variable
var table = $('#assignmentScores table');
// Which column is the score in? Find it here
var score_column = table.find('th:contains("Score")').index();
// Set up a regular expression for testing that the column contains something like '30/30'
var regex = /(\d+)\/(\d+)/;
// initialize the numerator and denomenator
var num = 0, den = 0;
// loop over all the table rows
table.find('tr').each(
function() {
  // get the value from the column that is the "Score" column
  var score = $(this).find('td:eq(' + score_column + ')').html();
  // Run the regular expression to get the matches
  var matches = regex.exec(score);
  // If there are matches, add them to numerator and denomenator
  if ($.isArray(matches) && typeof matches[2] != 'undefined') {
    num+= +matches[1];
    den+= +matches[2];
  }
});

// Calculate the percent - but only if we actually have a numerator / denomenator
percent = (num && den) ? (num / den) * 100 : 0;
// And, for fun, append the values to the table
table.append('<tr><td colspan="' + score_column + '" style="text-align:right;">Total:</td><td>' + percent.toFixed(1) + '%</td></tr>');

Javascript从页面计算成绩

1 个答案: