#pragma mark - WKNavigationDelegate   iOS8

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {

    // 类似 UIWebView 的 -webView: shouldStartLoadWithRequest: navigationType:

    NSString *url = [navigationAction.request.URL.absoluteString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    decisionHandler(WKNavigationActionPolicyAllow);

    if ([url isContainSubString:@"tel:"]) {

        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];

    }

}

或者 

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType

在这个方法中在 navigationType == UIWebViewNavigationTypeLinkClicked时

通过    [[request URL ]absoluteString]获取url的str   然后 

[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"tel:xxxx"]]]