html格式化显示

- (NSString *)flattenHTML:(NSString *)html trimWhiteSpace:(BOOL)trim {
    NSScanner *theScanner = [NSScanner scannerWithString:html];
    NSString *text = nil;
    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:@""];
    }
    html = [html stringByReplacingOccurrencesOfString:@" " withString:@""];
    // trim off whitespace
    return trim ? [html stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] : html;
}