$str ='<img src="test/aaa/a.jpg" widht=33 height=3><img src="f/aaa/a.jpg" widht=4 height=3>'如何批量将src前面加个域名呢$str ='<img src="http://xxxx.com/test/aaa/a.jpg" widht=33 height=3><img src="http://xxxx.com/f/aaa/a.jpg" widht=4 height=3>'