char accept[] = accept: */*;
char frmdata[] = param1=str1¶m2=str2¶m3=str3;
hinternet hsession = internetopen(myagent, internet_open_type_preconfig, null, null, 0);
hinternet hconnect = internetconnect(hsession, www.target.com, internet_default_http_port, null, null, internet_service_http, 0, 1);
hinternet hrequest = httpopenrequest(hconnect, post, filename.php, null, null, (lpcstr *)&accept, internet_flag_no_cookies , 1);
httpsendrequest(hrequest, content-type: application/x-www-form-urlencoded, -1, (lpvoid)frmdata, sizeof(frmdata));
internetclosehandle(hrequest);
internetclosehandle(hconnect);
internetclosehandle(hsession);
说明：
frmdata为表单数据，其中表单参数用&隔开；
httpopenrequest的第二个参数使用post，表示提交表单。