如何使用jquery检测文本以特殊单词开头的元素数?

var count = $("#sec div").filter(function(){
  return $(this).text().match(/^item/);
}).length;
console.log(count);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<section id="sec">
   <div id="item1">item1</div>
   <div id="item2">item2</div>
   <div id="item3">item3</div>
   <div id="abcitem1">abcitem1</div>
</section>

var childDivs = document.getElementById('sec')
           .getElementsByTagName('div');

var counter = Array.from(childDivs)
  .reduce((accumulator, currentValue) => {
    if (currentValue.innerHTML.startsWith('item')) {
      return accumulator = accumulator + 1;    
    }
    return accumulator;
}, 0);

console.log( counter );

<section id="sec">
   <div id="item1">item1</div>
   <div id="item2">item2</div>
   <div id="item3">item3</div>
   <div id="abcitem1">abcitem1</div>
</section>

var nodes = document.querySelectorAll('#sec div')
var count = 0
nodes.forEach(node => count += node.innerText.startsWith('item'))
console.log(count)

<section id="sec">
   <div id="item1">item1</div>
   <div id="item2">item2</div>
   <div id="item3">item3</div>
   <div id="abcitem1">abcitem1</div>
</section>

function checkItemsCount(section) {
  if (!section) return 0;
  const sec = document.querySelector(section);
  const items = sec.querySelectorAll('div');
  let count = 0;
  for (let i = 0; i < items.length; i++) {
    if (/^item/.test(items[i].innerText)) count++;
  }
  return count;
}

console.log(checkItemsCount('#sec'));

<section id="sec">
  <div id="item1">item1</div>
  <div id="item2">item2</div>
  <div id="item3">item3</div>
  <div id="abcitem1">abcitem1</div>
</section>