+ (NSString *)flattenHTML:(NSString *)html{
//去除html格式
NSScanner *theScanner;
NSString *text = nil;
theScanner = [NSScanner scannerWithString:html];
while ([theScanner isAtEnd] == NO) {
// find start of tag
[theScanner scanUpToString:@"<" intoString:NULL] ;
// find end of tag
[theScanner scanUpToString:@">" intoString:&text] ;
// replace the found tag with a space
//(you can filter multi-spaces out later if you wish)
html = [html stringByReplacingOccurrencesOfString:
[ NSString stringWithFormat:@"%@>", text]
withString:@""];
}
return html;
}