console 命令行工具 X clear

console

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title></title>
  </head>
  <body>
    <script>
      var str ="Rome was not built in a day";
      arr =str.replace(/\s/g);//去掉所有的空格
      var sum =0;
      for(var i of str)
      {
        sum++;
      }
      document.write(sum);
      
    </script>
  </body>