求IE6的地址栏 的网址获取和替换代码 Delphi

求IE6的地址栏 的网址获取和替换代码 Delphi求一段可以 获取 替换 IE6地址栏的代码 我知道通过句柄查找
我写了一段代码能找到句柄 但是替换不了
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var th1,th2,th3,th4,th5,th6,th7:Thandle;
 s:string;
begin
s:='http://www.iamhack.com';
th1:=FindWindow('IEFrame',nil);
if th1<>0 then
begin
///th2:=FindWindowEx(th1,0,'WorkerW',nil) ;
if th2<>0 then
beginth3:=FindWindowEx(th2,0,'ReBarWindow32',nil) ;
if th3<>0 then
beginth4:=FindWindowEx(th3,0,'ComboBoxEx32',nil) ;
if th4<>0 then
beginth5:=FindWindowEx(th4,0,'ComboBox',nil) ;
if th5<>0 then
beginth6:=FindWindowEx(th5,0,'Edit',nil) ;
if th6<>0 then
begin
showmessage(s);
SendMessage(th6,WM_SETTEXT,0,LPARAM(s));
end;
end;
end;
end;
end;
end;
end;