JavaScript 实现列表按字母排序

<!DOCTYPE html>
<html>
<head> 
<meta charset="UTF-8"> 
<title>JavaScript 实现列表按字母排序</title> 
</head>
<body>
<style>
 
</style>
 
<p>点击按钮按字母列表排序:</p>
<button onclick="sortList()">排序</button>
<ul id="id01">
  <li>Oslo</li>
  <li>Stockholm</li>
  <li>Helsinki</li>
  <li>Berlin</li>
  <li>Rome</li>
  <li>Madrid</li>
</ul>
<script>
function sortList() {
  var list, i, switching, b, shouldSwitch;
  list = document.getElementById("id01");
  switching = true;
  /*Make a loop that will continue until
  no switching has been done:*/
  while (switching) {
    //start by saying:no switching is done:
    switching = false;
    b = list.getElementsByTagName("LI");
    //Loop through all list items:
    for (i = 0; i < (b.length - 1); i++) {
      //start by saying there should be no switching:
      shouldSwitch = false;
      /*check if the next item should
      switch place with the current item:*/
      if (b[i].innerHTML.toLowerCase() > b[i + 1].innerHTML.toLowerCase()) {
        /*if next item is alphabetically lower than current item,
        mark as a switch and break the loop:*/
        shouldSwitch= true;
        break;
      }
    }
    if (shouldSwitch) {
      /*If a switch has been marked, make the switch
      and mark the switch as done:*/
      b[i].parentNode.insertBefore(b[i + 1], b[i]);
      switching = true;
    }
  }
}
</script>
</body>
</html>