WKWebView 通过JS控制HTML字体和图片的大小

- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation{
    // 页面加载完成之后调用
    [ webView evaluateJavaScript:
     @"var script = document.createElement('script');"
     "document.body.style.fontSize=28.0;"//设置字体大小
     "script.type = 'text/javascript';"
     "script.text = \"function ResizeImages() { "
     "var myimg,oldwidth;"
     "var maxwidth = window.innerWidth;" // UIWebView中显示的图片宽度
     "for(i=1;i <document.images.length;i++){"
     "myimg = document.images[i];"
     "oldwidth = myimg.width;"
     "myimg.width = maxwidth;"
     "}"
     "}\";"
     "document.getElementsByTagName('head')[0].appendChild(script);ResizeImages();" completionHandler:nil];

}