xiebiji.com

if(@file_get_contents("http://community.csdn.net/ui/homepage/images/questions.gif"))
echo 'Y';
else
echo 'N';

if(@fopen("http://community.csdn.net/ui/homepage/images/questions.gif"))
echo 'Y';
else
echo 'N';

function   isExist(url)     
  {   
  xmlhttp   =   new   ActiveXObject("Microsoft.XMLHTTP")   
  xmlhttp.open("GET",url,false)   
  xmlhttp.send()   
  if(xmlhttp.status==200)   
  return true;   
  else   
  return false;
  }