UIwebView的html字符串高度计算

if (!webviewHasLoaded && pdIntroduce.length>0) {
            webView = [[UIWebView alloc]initWithFrame:CGRectMake(10, 30 , DEVW-20, webviewH)];
            webView.delegate = self;
            [webView loadHTMLString:pdIntroduce baseURL:nil];
            webviewHasLoaded = YES;
        }
         [cell.contentView addSubview:webView];
//当reload的时候，如果重新创建了cell，就必须把 cell.contentview放在{}外面。

- (void)webViewDidFinishLoad:(UIWebView *)wb
{
    NSString *height_str = [wb stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"];
　　//document.body.offsetHeight获取页面高度信息
    int temp = (int)height_str.integerValue + 10;
    if (temp != webviewH) {
        webviewH = temp;
        webView.frame = CGRectMake(10,30, DEVW-20, webviewH);
        //webviewHasLoaded=NO;
        webView.scrollView.scrollEnabled = NO;  //禁止滚动
        [TrainTab reloadData];
    }