方法1：网页标签对处理
- (NSAttributedString *)attrHtmlString:(NSString *)str{
str = [NSString stringWithFormat:@"<html><meta content=\"width=device-width, initial-scale=1.0, maximum-scale=3.0, user-scalable=0; \" name=\"viewport\" /><body style=\"overflow-wrap:break-word;word-break:break-all;white-space: normal; font-size:15px; color:#ffffff; \">%@</body></html>",str];
NSAttributedString*attrStr= [[NSAttributedString alloc] initWithData:[str dataUsingEncoding:NSUTF8StringEncoding] options:@{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:@(NSUTF8StringEncoding)} documentAttributes:nil error:nil];
return attrStr;
}
