点击webView中链接，开系统safari，不在webView里面跳转

直接粘贴这段代码就行（别忘了实现UIWebViewDelegate）

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
    NSURL *requestURL = [request URL];
    if (([[requestURL scheme] isEqualToString:@"http"]||[[requestURL scheme] isEqualToString:@"https"]||[[requestURL scheme] isEqualToString: @"mailto"])
        && (navigationType == UIWebViewNavigationTypeLinkClicked)){
        return ![[UIApplication sharedApplication] openURL:requestURL];
    }
    return YES;
}