webview 等比缩放

- (void)webViewDidFinishLoad:(UIWebView *)webView 

 {    

  [webView stringByEvaluatingJavaScriptFromString:@"document.body.style.zoom=0.5"]; 

 }

修改网页表头内容：

 NSString *meta = [NSString stringWithFormat:@"document.getElementsByName(\"viewport\")[0].content = \"width='width-device', initial-scale=2.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=yes\""];  

 [webView stringByEvaluatingJavaScriptFromString:meta];