您好我想知道如何获取产品页面中数量字段的当前值？ 获得当前值后，我只想修改输入字段步骤。 例如：
$ sbcl --load ./cl-jupyter.lispThis is SBCL 1.3.1.debian, an implementation of ANSI Common Lisp.
More information about SBCL is available at <http://www.sbcl.org/>.
SBCL is free software, provided as is, with absolutely no warranty.
It is mostly in the public domain; some portions are provided under
BSD-style licenses. See the CREDITS and COPYING files in the
distribution for more information.
... initialization mode... please wait...
To load "cl-jupyter":
Load 1 ASDF system:
cl-jupyter
; Loading "cl-jupyter"
.........; cc -o /home/keys/.cache/common-lisp/sbcl-1.3.1.debian-linux-x64/home/keys/quicklisp/dists/quicklisp/software/pzmq-20170403-git/grovel__grovel-tmpGHU3ALSV.o -c -m64 -fPIC -I/home/keys/quicklisp/dists/quicklisp/software/cffi_0.19.0/ /home/keys/.cache/common-lisp/sbcl-1.3.1.debian-linux-x64/home/keys/quicklisp/dists/quicklisp/software/pzmq-20170403-git/grovel__grovel.c
/home/keys/.cache/common-lisp/sbcl-1.3.1.debian-linux-x64/home/keys/quicklisp/dists/quicklisp/software/pzmq-20170403-git/grovel__grovel.c:6:17: fatal error: zmq.h: file not found
compilation terminated.
While evaluating the form starting at line 5, column 0
of #P"/home/keys/cl-jupyter/./cl-jupyter.lisp":
debugger invoked on a CFFI-GROVEL:GROVEL-ERROR in thread #<THREAD "main thread" RUNNING {100399C6A3}>: Subprocess (:PROCESS #<SB-IMPL::PROCESS :EXITED 1>)
with command ("cc" "-o" "/home/keys/.cache/common-lisp/sbcl-1.3.1.debian-linux-x64/home/keys/quicklisp/dists/quicklisp/software/pzmq-20170403-git/grovel__grovel-tmpGHU3ALSV.o" "-c" "-m64" "-fPIC" "-I/home/keys/quicklisp/dists/quicklisp/software/cffi_0.19.0/" "/home/keys/.cache/common-lisp/sbcl-1.3.1.debian-linux-x64/home/keys/quicklisp/dists/quicklisp/software/pzmq-20170403-git/grovel__grovel.c")
exited with error code 1
Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.
restarts (invokable by number or by possibly-abbreviated name):
0: [RETRY ] Retry PROCESS-OP on #<GROVEL-FILE "pzmq" "grovel">.
1: [ACCEPT ] Continue, treating PROCESS-OP on #<GROVEL-FILE "pzmq" "grovel"> as having been successful.
2: Retry ASDF operation.
3: [CLEAR-CONFIGURATION-AND-RETRY] Retry ASDF operation after resetting the configuration.
4: [ABORT ] Give up on "cl-jupyter"
5: [RETRY ] Retry EVAL of current toplevel form.
6: [CONTINUE ] Ignore error and continue loading file "/home/keys/cl-jupyter/./cl-jupyter.lisp".
7: Abort loading file "/home/keys/cl-jupyter/./cl-jupyter.lisp".
8: Ignore runtime option --load "./cl-jupyter.lisp".
9: Skip rest of --eval and --load options.
10: Skip to toplevel READ/EVAL/PRINT loop.
11: [EXIT ] Exit SBCL (calling #'EXIT, killing the process).
(CFFI-GROVEL:GROVEL-ERROR "~a" #<UIOP/RUN-PROGRAM:SUBPROCESS-ERROR {100691C9F3}>)