highlight cell if isblank vba - vba

Question

Hi i have the following code but it prommpts an error range of object_worksheet failed. I'm not sure what i'm doing wrong (i've found the vba code using record macro and simply copy and pasted except i've replaced all of selection to ws.range(emptyrow) to indicate the range is up to the last cell with values. Also, if i were to change the sub to sub highlightemptycell_change() and have if statement as such: "if any cells are changed then do the following" how would i write that in a vba language?
sub highlightemptycell()
Dim ws As Worksheet
Dim r As Range
Dim emptyrow As Long
Dim err As Range
Set ws = Worksheets("Master")
emptyrow = ws.Cells(Rows.Count, 1).End(xlUp).Row + 1 '<<< safer....
ws.Range(emptyrow).FormatConditions(1).StopIfTrue = False
ws.Range(emptyrow).FormatConditions.Add Type:=xlExpression, Formula1:= _
"=ISBLANK(ws.range(emptyrow)"
ws.Range(emptyrow).FormatConditions(ws.Range(emptyrow).FormatConditions.Count).SetFirstPriority
With ws.Range(emptyrow).FormatConditions(1).Interior
.PatternColorIndex = xlAutomatic
.Color = 5287936
.TintAndShade = 0
End With

Answer 1

I'm not sure exactly what you are doing. In particular, I'm not sure of the significance of this line,
ws.Range(emptyrow).FormatConditions(1).StopIfTrue = False
especially when there are no conditional formats in the cell at the time it is executed.
But the following macro seems to do what yours would do if it were cleaned up a bit and written with proper syntax
Option Explicit
Sub highlightemptycell()
Dim ws As Worksheet
Dim r As Range
Dim emptyrow As Long
Dim err As Range
Dim rEmptyRow As Range '<-- range object added to use below
Set ws = Worksheets("Master")
Set rEmptyRow = ws.Cells(ws.Rows.Count, 1).End(xlUp).Offset(rowoffset:=1) '<<< safer....
With rEmptyRow.FormatConditions
If .Count > 0 Then .Item(1).StopIfTrue = False
.Add Type:=xlExpression, Formula1:= _
"=ISBLANK(" & rEmptyRow.Address & ")"
.Item(.Count).SetFirstPriority
With .Item(1).Interior
.PatternColorIndex = xlAutomatic
.Color = 5287936
.TintAndShade = 0
End With
End With
End Sub