UIWebView获得内容的高－作出自适应高的UIWebView

1 - (void)webViewDidFinishLoad:(UIWebView *)webView
2 {    
3 NSString *height_str= [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"];
4     int height = [height_str intValue];
5     webView.frame = CGRectMake(0,0,320,height);
6     NSLog(@"height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"]);
7 }