如何为变量赋值并在windows批处理程序中检查它是否为空？

Here is the code i wrote:

这是我写的代码:

 @echo off
:top
set chkScheduleTime=""
set chkScheduleName=""


set /p scheduleName=Enter the name of the schedule?
cls
set /p scheduleTime=Enter the time to schedule task?
cls


set chkScheduleTime=%scheduleTime =%
set  chkScheduleName=%scheduleName =%

IF /I "%chkScheduleName%"=="" ( 
    set errorMessage=*Name of schedule required 
)


IF /I "%chkScheduleTime%"=="" (
    set errorMessage=%errorMessage% *Time of schedule required 
)

IF NOT defined "%errorMessage%" (

    echo %errorMessage%
    pause
    cls
    goto top
)




echo Schedule Name %scheduleName% 
echo.
echo Time: %scheduleTime%


:end
 @echo o