ASP Conversion help

[mrbaseball34]

I'm trying to convert some ASP to PHP and came across this:

   datCurrent = CDate(intMonth & "/1/" & intYear)
   intCurrentMonthDays = _
      Day(DateAdd("d", -1, DateAdd("m", 1, datCurrent)))
   intWeekday = Weekday(datCurrent)

What would be the PHP equivalent?

intMonth and intYear are passed as variables in the function call.