从"td"字符串中提取字符标签

你可以用下面的代码来做，但是你格式化参数的方式有点奇怪，如果格式不正确可能会产生错误。

var parameters = ["rk1/1/3 and rk2/1/4", "rk2/2/1 and rk3/3/3", "rk2/2/2 and rk3/4/3"];
// For each set of parameters, execute extract_content
for (var i = 0; i < parameters.length; i++) {
  console.log('Result for "' + parameters[i] + '":');
  console.log(extract_content(parameters[i]));
}
function extract_content(params) {
  // Split selections, to get something like ["rk1/1/3", "rk2/1/4"]
  var selections = params.split(' and '),
      res = '';
  // For each selection
  for (var i = 0; i < selections.length; i++) {
    // Split it on slashes, to get ["rk1", "1", "3"]
    var parts = selections[i].split('/'),
        // Get the element with ID "rk1_1"
        elem = document.getElementById(parts[0] + '_' + parts[1]);
    // If the element exists
    if (elem) {
      // Add the character at position X to the result
      res += elem.textContent.trim()[parts[2] - 1];
    }
  }
  // Convert result to a number and return it
  return res;
}

<table>
  <tr>
    <td id="rk1">First RK</td>
    <td id="rk1_1">09231</td>
  </tr>
  <tr>
    <td id="rk2">Second RK</td>
    <td id="rk2_1">60234</td>
    <td id="rk2_2">69260</td>
  </tr>
  <tr>
    <td id="rk3">Third RK</td>
    <td id="rk3_1">30224</td>
    <td id="rk3_2">30302</td>
    <td id="rk3_3">20280</td>
    <td id="rk3_4">82122</td>
  </tr>
</table>