PHP is getting all of the IMG attribute values, including SRC, and so on, save one, I do not understand the regular AH

? PHP/*php Regular extract image any attribute in img tag * * * $str   =   ' <center><br"/>php is to extract or change the image in the IMG tag any property </center> '; 1, take the entire picture code Preg_match ('/<\s*img\s+[^>]*?src\s*=\s* (\ ' |\ ')) (. *?) \\1[^>]*?\/?\s*>/i ', $str, $match); echo $match [0]; 2, take the width preg_match ('//i ', $str, $match); echo $match [1]; 3, take the height Preg_match ('//i ', $str, $match); echo $match [1]; 4, take src preg_match ('//i ', $str, $match); echo $match [1]; /*php Replace any attributes in the IMG tag of the picture///1, replace src= "/uploads/images/20100516000.jpg" with src= "/uploads/uc/images/20100516000.jpg") Print Preg_replace ('/()/I ', "\${1}uc/images/\${3}", $STR); echo "