第一步：給webview新增kvo監聽content size

[self.webView.scrollViewaddObserver:selfforKeyPath:@"contentSize"options:NSKeyValueObservingOptionNewcontext:nil];

第二步：實現監聽

#pragma mark - KVO

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void

{

    if ([keyPath isEqualToString:@"contentSize"]) {

        CGSize contentSize = [self.webView sizeThatFits:CGSizeZero];

        self.webView.frame = CGRectMake(0, 0, contentSize.width, contentSize.height);

        [self.tableView reloadData];

    }

}

第三步：直接返回高度

returnself.webView