批处理显示跑秒

@echo off &title DOS资源站 www.cmdos.net
mode con cols=30 lines=4&title 跑秒
echo.
echo      press to 开始计时
pause>nul
set var=%time%
set /a var1=%var:~6,2%
set /a var2=%var:~9,2%
cls&echo.&for /l %%i in (1,1,10) do set/p= <nul

:loop
set var=%time%
if %var:~6,2% geq %var1% (set /a var3=%var:~6,2%-%var1%) else (set /a var3=60-%var1%+%var:~6,2%) 2>nul
if %var:~9,2% geq %var2% (set /a var4=%var:~9,2%-%var2%) else (set /a var4=100-%var2%+%var:~9,2%) 2>nul
set var3=0%var3%&set var4=0%var4%
set var3=%var3:~-2%&set var4=%var4:~-2%
set/p=%var3% . %var4%<nul&set/p=<nul
echo %var3% . %var4%>timecost.txt
goto loop