Loadrunner的检查点有三种：Web_find、Web_reg_find和Web_image_check。至于为什么要用检查点可以用个小例子做个测试，例如一个登陆脚本登陆的账号为123456，密码为123456，可以正确登陆，当把账号或密码改掉再执行，发现脚本并没有报错，也顺利执行下来了。原因是什么呢 ？Loadrunner以用户角色向服务器发送一个登陆请求，却不会判断请求的返回消息是什么，只要有返回，即使这是个拒绝登陆的返回，Loadrunner也认为登陆成功了。所以在登录或者其他有重要页面跳转的地方，很有必要做检查点。
在脚本里面加检查点，基本不影响性能，有的人说在做场景压力测试时要把检查点代码屏蔽，我觉得没什么必要。
Web_find和Web_image_check两个函数如果在脚本里面增加，需要在设置中打开“图像和文本检查”功能，该功能默认是不打开的，如果手工在脚本里面添加检查点，系统会有提示：
Action.c(43): Verification checks not enabled. web_find is skipped. See the 'Run-time settings/Preferences/Checks'
[MsgId: MMSG-27197]
下面对这三个检查点简单做一下小结：
Web_find和Web_image_check两个函数如果在脚本里面增加，需要在设置中打开“图像和文本检查”功能，该功能默认是不打开的，如果手工在脚本里面添加检查点，系统会有提示：
Action.c(43): Verification checks not enabled. web_find is skipped. See the 'Run-time settings/Preferences/Checks'
[MsgId: MMSG-27197]
下面对这三个检查点简单做一下小结：
1、Web_find
Web_find只能在html的录制模式下查找html页面文字，查找速度慢，并且要在html请求结束后才会去查找（即这个函数需要写在html请求脚本后面），下面是在手册上对这个函数的限制描述：
The web_find function searches an HTML page for a specified text string. web_find is deprecated. It has been replaced with web_reg_find.
This function is limited to HTML-based recorded scripts (see Recording Options > Recording tab). It searches the context only after the HTML request is complete, resulting in slower execution time than web_reg_find.
The web_find function has been superseded in C Language scripts by web_reg_find, which runs faster and can be used in both HTML-based and URL-based recording. web_find is supported in C for backward compatibility. In Java and Visual Basic, it has not been superseded.
The web_find function is not supported for WAP scripts running in HTTP or Wireless Session Protocol (WSP) replay mode.
This function is limited to HTML-based recorded scripts (see Recording Options > Recording tab). It searches the context only after the HTML request is complete, resulting in slower execution time than web_reg_find.
The web_find function has been superseded in C Language scripts by web_reg_find, which runs faster and can be used in both HTML-based and URL-based recording. web_find is supported in C for backward compatibility. In Java and Visual Basic, it has not been superseded.
The web_find function is not supported for WAP scripts running in HTTP or Wireless Session Protocol (WSP) replay mode.
例如Loadrunner自带的订票程序在登陆后有这么一段文字描述：
Welcome, jojo, to the Mercury Tours reservation pages.
Using the menu to the left, you can search for new flights to book, or review/edit the flights already booked. Don't forget to sign off when you're done!
我们可以在对应页面的url脚本后面做如下的检查点：
web_find("web_find","What=Don't forget to sign off when you're done!",LAST);
运行脚本结果如下：
Action.c(43): "web_find" successful. 1 occurrence(s) of "Don't forget to sign off when you're done!" found (RightOf="", LeftOf="")[MsgId: MMSG-27196]
也可以这么增加：
web_find("web_find","RightOf=Don't forget to s","LeftOf=gn off when you're done!","What=i",LAST);
运行脚本结果如下：
Action.c(46): "web_find" successful. 1 occurrence(s) of "i" found (RightOf="Don't forget to s", LeftOf="gn off when you're done!")[MsgId: MMSG-27196]
这块有一点需要注意，RightOf和LeftOf并不是指右边和左边边界，而是指要查找的“i”在RightOf的右边，在LeftOf的左边。
2、Web_reg_find
Web_reg_find是注册类型函数，它本身并不执行，不能通过它的返回值来作为事务的判断条件（因为web_reg_find()的返回值0和1表示web_reg_find()是否注册成功，并不代表查找的内容是否存在，也就是说无论查找的文本内容是否存在，都返回0。它是从返回的缓冲区扫描而不是在接收的页面中查找。这是比web_find更高效的一个函数。web_reg_save_param也是注册类函数，需要放到请求的页面之前，而且查找的内容是服务器返回的缓冲数据中查找，所以查找内容应该看html源代码的内容。
下面同样做两个例子：
例1：
web_reg_find("Text=sign",LAST);
运行脚本结果如下：
Action.c(34): Registered web_reg_find successful for "Text=sign" (count=3)[MsgId: MMSG-26364]
例2：
利用web_reg_find创建的参数SaveCount ，作为判断条件
web_reg_find("Text=sign", "SaveCount=para_count", LAST);
web_url("Home Button",
"URL=http://127.0.0.1:1080/mercuryWebTours/welcome.pl?page=menus",
"TargetFrame=body",
"Resource=0",
"RecContentType=text/html",
"Referer=http://127.0.0.1:1080/mercuryWebTours/nav.pl?page=menu&in=itinerary",
"Snapshot=t8.inf",
"Mode=HTML",
LAST);
if (atoi(lr_eval_string("{para_count}"))>0)
lr_output_message("Login on succesful!");
else
lr_error_message("Login on fail!");
运行脚本结果如下：
Action.c(48): Login on succesful!
在使用web_reg_find时有一点需要注意，如果抓取的是中文，不要用utf8格式，否则抓到的都是乱码，运行总是不会成功。
3、Web_image_check
这个函数比较简单，写在对应的web_ur后面即可：
web_url("Home Button",
"URL=http://127.0.0.1:1080/mercuryWebTours/welcome.pl?page=menus",
"TargetFrame=body",
"Resource=0",
"RecContentType=text/html",
"Referer=http://127.0.0.1:1080/mercuryWebTours/nav.pl?page=menu&in=itinerary",
"Snapshot=t8.inf",
"Mode=HTML",
LAST);
web_image_check("web_image_check","src=/images/signoff.gif",LAST);
执行结果如下：
Action.c(42): "web_image_check" succeeded (1 occurrence(s) found. Alt="", Src="/images/signoff.gif")[MsgId: MMSG-27192]
Action.c(42): web_image_check was successful[MsgId: MMSG-26392]
这里说明一下对应的src可以在脚本执行后的日志里面找到，日志记录的是完整路径，src部分只要相对路径就可以了。
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后面补充了张图片 
