UserAgent - 用户代理头,随请求一起发送。这里不会对该参数是否和运行时设置中射的浏览器User-Agent是否一致匹配。.
  例子:
web_url("www.phpwind.net",
"URL=http://www.phpwind.net/",
"TargetFrame=",
"Resource=0",
"RecContentType=text/html",
"Referer=",
"Snapshot=t14.inf",
"Mode=HTML",
EXTRARES,
"Url=/themes/site/link2015/images/common/navBbg.png", ENDITEM,
"Url=/themes/site/link2015/images/common/headbg.png", ENDITEM,
"Url=/themes/site/link2015/images/forum/new.gif", ENDITEM,
"Url=/themes/site/link2015/images/design/mode_h_bg.png", ENDITEM,
"Url=/themes/site/link2015/images/common/search.png", ENDITEM,
"Url=/themes/site/link2015/images/common/nav_cur.png", ENDITEM,
"Url=/themes/site/link2015/images/forum/old.gif", ENDITEM,
"Url=/themes/site/link2015/images/common/nav_hover.png", ENDITEM,
"Url=/themes/site/link2015/images/common/head_icon.png", ENDITEM,
"Url=/res/js/dev/jquery.js?v=20141124", ENDITEM,
"Url=http://c.cnzz.com/core.php?web_id=30051218&t=q", ENDITEM,
"Url=/themes/site/link2015/images/common/core_bg.png", ENDITEM,
"Url=/res/js/dev/pages/common/global.js?v=20141124", ENDITEM,
"Url=/res/js/dev/ui_libs/tabs/tabs.js?v=20141124", ENDITEM,
LAST);
  关于EXTRARES的说明:
  EXTRARES,
  "Url=/themes/site/link2015/images/common/navBbg.png", ENDITEM,
  "Url=/themes/site/link2015/images/common/headbg.png", ENDITEM,
  "Url=/themes/site/link2015/images/forum/new.gif", ENDITEM,
  "Url=/themes/site/link2015/images/design/mode_h_bg.png", ENDITEM,
  "Url=/themes/site/link2015/images/common/search.png", ENDITEM,
  ……
  以上这一段内容说明在载入这个页面时还有其它图片或附属资源需要下载。由于默认的web_url或web_link函数是使用HTML Mode的,所以无论脚本中是否存在EXTRARES段,在完成函数的时候都会自动下载该HTML对应的所有资源。EXTRARES段是一种扩展验证机制,验证这些对象是否存在,如果EXTRARES中的资源请求并存在请求返回内,那么回放该脚本会比真实情况略微增加带宽的使用。
  扩展:
  1)如果EXTRARES段中请求的地址和主请求相同,则不会产生新的流量
  2)录制得到的EXTRARES不是简单地将图片拆出,而是主请求请求不到的内容,例如css中的图片引用或favicon.ico
  3)错误的EXTRARES会产生额外的请求。
  在普通脚本开发中为了更好地模拟用户请求,好别删EXTRARES段,多了没啥坏处,只是多了一点数据流量,删除了会导致某些主请求请求不到的内容不会被请求。
  官网例子:
Example 1 – 发送一个访问abc.com的HTTP GET请求。
web_url("www.abc.com",
"URL=http://www.abc.com/",
"TargetFrame=",
"TargetBrowser=Mercury Technologies",
"Resource=0",
"RecContentType=text/html",
"Snapshot=t1.inf",
"Mode=HTML",
LAST );
Example 2 –发送一个带引用页面的请求
web_url("Hit the Slopes and Save",
"URL=http://www.saleserver.com/American?BV_EngineID=
..fm_ski_sale_fall00guest.html",
"TargetFrame=Main",
"Resource=0",
"RecContentType=text/html",
"Referer=http://www.saleserver.com/American?BV_Operation=
Dyn_Frame&..main–guest.tmpl",
"Snapshot=t3.inf",
"Mode=HTML",
LAST );
Example 3– 下载一个ftp服务器上的游戏
web_url("Games",
"URL=ftp://joe:secret@mygames.com/games/archive/loderunner.exe",
"FtpAscii=1",
LAST );
Example 4– 登陆到一个安全站点
web_url("Login",
"URL=https://secure.computing.com/scripts/login.asp?
user=(username)&session={ssid}",
"RecContentType=text/html", //Expected content–type