webView 设置手势缩放

1) webView初始化时设置属性

    UIWebView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 64, IphoneWidth,  IphoneHeight - 64)];
    webView.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);  
    webView.scalesPageToFit = YES;  
    webView.multipleTouchEnabled = YES;  
    webView.userInteractionEnabled = YES;  
    webView.scrollView.scrollEnabled = YES;  
    webView.contentMode = UIViewContentModeScaleAspectFit;  
    webView.delegate = self; 
    self.webView = webView;

2) 如果设置了上述的属性网页依旧不可以缩放，则在UIWebView代理方法中添加：

- (void)webViewDidFinishLoad:(UIWebView *)webView {
   NSString *jsMeta = [NSString stringWithFormat:@"var meta = document.createElement('meta');meta.content='width=device-width,initial-scale=1.0,minimum-scale=.5,maximum-scale=3';meta.name='viewport';document.getElementsByTagName('head')[0].appendChild(meta);"];
   [self.webView stringByEvaluatingJavaScriptFromString:jsMeta];
}