Passing tablename as argument into function

[gouse]

Create or replace function Test(strTable in text) return bigint as
$$
declare
intSum bigint;
begin
intSum:=(Select sum(salary) from strTable);
return intSum;
end;
$$
language plpgsql;

select Test('Employee' );

I want to pass Table name as a argument into function and execute select statement on this table
I run this function error is occure

[rski]

Select sum(salary) from strTable

to do that you have to put execute clause (it is a dynamic query).