我这段代码为什么文本打印不出来?
<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>系好安全带,准备启航</title> <script type="text/javascript"> document.write("文本"); function ocan(){ var mychar="文本1"; alert(mychar); } </script> </head> <body> <form> <input name="button" type="button" value="启航" onclick="ocan()" /> </form> </body> </html>