html页面一般都会指定一个编码，如何获取到是处理html页面的第一步，因为错误的编码必然带来后面处理的问题。这里我用python的正则表达式写了个：
import re
a = ["<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />",
'<meta http-equiv=Content-Type content="text/html;charset=gb2312">',
'<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">',
'<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />',
'<meta http-equiv="content-type" content="text/html; charset=utf-8" />',
'<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />',
'<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />'
]
b = "<meta[ ]+http-equiv=["']"']"']"']"
B = re.compile(b, re.IGNORECASE)
for ax in a:
r1 = B.search(ax)
if r1:
print r1.group()
print r1.group(1), len(r1.group())
else:
print 'not match'