关于document.write()?
<html> <head> <title> Untitled Document </title> <script type ="text/javascript"> // 同样的两次调用document.write(),为什么一会发生错误，一个不会? function learn_write_wrong(){ var pre = document.getElementsByTagName("pre"); document.write(pre[0].innerHTML, "<br />"); document.write(pre[0].id, "<br />"); // 这句话发生了错误! why? } function learn_write_right(){ document.write("right", "<br />"); document.write("right yeah!", "<br />"); } </script> </head> <body> <pre id = "实验document.write()方法"> 网页原内容 </pre> <input type = "button" value = "错误" onclick = "javascript: learn_write_wrong();" /> <input type = "button" value = "正确" onclick = "javascript: learn_write_right();" /> </body></html>