求高手帮注释下下面获取网页源代码的程序，谢谢~~

CInternetSession httpSession(NULL,0);
CHttpFile* pHttpFile=NULL;
CString text; UpdateData(TRUE);
m_sURL.MakeLower();
m_sURL.TrimLeft(" ");
m_sURL.TrimRight(" ");
if(m_sURL.Find("http://")!=0)
m_sURL=CString("http://") + m_sURL;
m_sResource="连接到站点"+m_sURL+"\r\n"; BeginWaitCursor();
pHttpFile=(CHttpFile*)httpSession.OpenURL(m_sURL);
if(pHttpFile==NULL)
{
EndWaitCursor();
m_sResource+="Bad URL!\r\n";
UpdateData(FALSE);
return;
}
while(pHttpFile->ReadString(text))
{
m_sResource=m_sResource+"\r\n";
m_sResource+=text;
} EndWaitCursor();
pHttpFile->Close();
httpSession.Close();
UpdateData(FALSE);