function replacestr(const s, srch, replace: string): string;
var
i : integer;
source: string;
begin
source:= s;
result:= '';
repeat
i:=pos(srch, source);
if i > 0 then begin
result := result + copy(source,1,i-1) + replace;
source := copy (source,i+length(srch),maxint);
end
else
result := result + source;
until i<=0;
end;

function HTTPTran(St : String) : String;
var i : Integer;
begin
  Result:='';
  for i:=1 to length(St) do
    if St[i] in ['a'..'z','A'..'Z','0','1'..'9'] then
      Result:=Result+St[i]
    else if St[i]=' ' then
      Result:=Result+'+'
    else
      Result:=Result+'%'+IntToHex(Byte(St[i]),2);
end;