console 命令行工具 X clear

console

function createNewDoc()
  {
  var newDoc=document.open("text/html","replace");
  var txt="<html><body>学习 DOM 非常有趣！</body></html>";
  newDoc.write(txt);
  newDoc.close();
  }

<input type="button" value="打开并写入一个新文档" onclick="createNewDoc()">