UIWebView算高度

CGSize fittingSize = [webView sizeThatFits:CGSizeZero];
   CGFloat height = fittingSize.height;

 CGFloat height = [[webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"] floatValue];

     CGFloat height =  self.webView.scrollView.contentSize.height;

// 判断webView是否完全加载完数据 
+ (BOOL)isFinishLoadingWith:(UIWebView *)webView{
    NSString *readyState = [webView stringByEvaluatingJavaScriptFromString:@"document.readyState"];
    BOOL complete = [readyState isEqualToString:@"complete"];
    if (complete && !webView.isLoading) {
        return YES;
    }else{
        return NO;
    }
}

//kvo方式