- (void)setSource:(NSString *)source
{
NSRange range;
range.location = [source rangeOfString:@">"].location + 1;
range.length = [source rangeOfString:@"</"].location - range.location;
//range.length = [source rangeOfString:@"<"options:NSBackwardsSearch].location - range.location;
_source = [NSString stringWithFormat:@"来自%@",[source substringWithRange:range]];
}

判定是否有gif，无视大小写