webview高度自适应

-(void)webViewDidFinishLoad:(UIWebView *)webView
{
//获取页面高度（像素）
    NSString * clientheight_str = [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"];
    float clientheight = [clientheight_str floatValue];
    //设置到WebView上
    webView.frame = CGRectMake(0, 0, SCREEN_WIDTH, clientheight);
    //获取WebView最佳尺寸（点）
    CGSize frame = [webView sizeThatFits:webView.frame.size];
    //获取内容实际高度（像素）
    NSString * height_str= [webView stringByEvaluatingJavaScriptFromString: @"document.getElementById('webview_content_wrapper').offsetHeight + parseInt(window.getComputedStyle(document.getElementsByTagName('body')[0]).getPropertyValue('margin-top'))  + parseInt(window.getComputedStyle(document.getElementsByTagName('body')[0]).getPropertyValue('margin-bottom'))"];
    float webHeight = [height_str floatValue];
    //内容实际高度（像素）* 点和像素的比
    webHeight = webHeight * frame.height / clientheight;
    //再次设置WebView高度（点）
    webView.frame = CGRectMake(0, 0, self.view.frame.size.width, height);
}