run javscript from code behind if some condition match

Hi,
i want to run javscript from code behind if some condition match

In page load i have a sub progrme

Private Sub  Runscript()
' Execute javascript some condition match
dim i as integer=0

if i=0 then
'execute javascript alert

end if

End Sub

and javascript is
function Alert() {
           alert("Hai");
             

        }
i am calling this some sub programme Runscript in pageload


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