parsing data

import urllib2
website = ''
findstr = ''
def urlfinder(html,string):
    #condition
    i = 0
    if html.find(string) == -1:
        print 'Web site khong co muc "' + string + ' nay'
        return 0
    if (html.find(string) != -1) or (html.find(string) != 0):
        while i >= 0:
            if html[html.find(string)+len(string)+i] == '<' and html[html.find(string)+len(string)+i+1] == '/':
                return html[html.find(string)+len(string)+1:html.find(string)+len(string)+i]
                break
            i = i + 1
temp = urllib2.urlopen(website)
data = temp.read()
datastr= urlfinder(data,findstr)
print datastr[1:len(datastr)]