写一句诗。诗的最初状态是隐藏的，效果是让诗缓慢出现，直到显示完全
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>无标题文档</title> </head> <style type="text/css"> * { margin:0px; padding:0px; } #b { font-family:Georgia, "Times New Roman", Times, serif; font-size:40px; font-weight:bold; 1000px;//设置诗句的宽度 height:50px;//设置诗句的高度 } </style> <body> <div id="a" style="0px;height:50px;overflow:hidden">--诗句宽度初始为0 <div id="b" >我是人间惆怅客，知君何事泪纵横，断肠声里忆平生！</div> </div> </body> <script type="text/javascript"> show(); function show() { var s=document.getElementById("a"); if(parseInt(s.style.width)<1000)//如果a的宽度小于500px,（把a的宽度转为整数） { var w=parseInt(s.style.width)+1; s.style.width=w+"px";//拼接字符串 window.setTimeout("show()",20);//每隔20毫秒字符宽度加1px } } </script> </html>