console 命令行工具 X clear

console

 window.onload = function ()
        {
            document.body.innerHTML = '<input id="btn" type="button" value="按钮">';
            var YYDS = document.createElement("input"); 
            document.body.appendChild(YYDS);
            YYDS.type = "button";
            YYDS.value = "按钮2";
            YYDS.id = "btn";
        }

<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
</head>
<body>
</body>
</html>