：js遍历table某一列内容出现的次数记录

<script>

function countvalueshow(myTable,colindex){

const table = document.getElementById(myTable);

const rows = table.getElementsByTagName('tr');

const colCount = colindex; // 第二列的索引是1，因为索引从0开始计算

let countMap = {};

for (let i = 1; i < rows.length; i++) { // 跳过表头

  const cell = rows[i].getElementsByTagName('td')[colCount];

  const age = cell.textContent.trim();

  if (countMap[age]) {

    countMap[age]++;

  } else {

    countMap[age] = 1;

  }

}

console.log(countMap);

return countMap;

}

countvalueshow('myTable',1)

</script>