UIWebView与OC相互调用

//js.html文件  
<input type="button" value="testClick" onclick="testClick({'params.key' : 'params.value'})"/>

<input type="button" value="testShowMessage" onclick="testShowMsg()"/>

//  ViewController.m
//  31-webview调用OC

#import "ViewController.h"
#import <JavaScriptCore/JavaScriptCore.h>



@interface ViewController () <UIWebViewDelegate>

@property (weak, nonatomic) IBOutlet UIWebView *wv;

@property (nonatomic, strong) JSContext *jsContext;

@end



@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //创建URL
    NSURL *url = [[NSBundle mainBundle] URLForResource:@"js.html" withExtension: nil];
    //创建请求
    NSURLRequest *request = [NSURLRequest requestWithURL: url];
    //发送加载网页请求
    [self.wv loadRequest: request];

}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    if (!self.jsContext) {
        self.jsContext = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
        
        // 关联打印异常
        self.jsContext.exceptionHandler = ^(JSContext *context, JSValue *exceptionValue) {
            context.exception = exceptionValue;
            NSLog(@"异常信息：%@", exceptionValue);
        };
        
        //一个block函数给js调用 注意调用此函数是在webView线程
        self.jsContext[@"testClick"] = ^(NSDictionary *param) {
            NSLog(@"js调用oc testClick函数 成功.参数是:\n%@", param);
        };
        //注意调用时并不在主线程
        self.jsContext[@"testShowMsg"] = ^() {
            NSLog(@"js调用oc testShowMsg函数 成功");
            UIAlertView *alertV = [[UIAlertView alloc] initWithTitle:@"提示" message:@"调用成功" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil];
            [alertV show];
        };

        //这句可以不写 好像是返回一些浏览器的信息
        id userAgent = [webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
        NSLog(@"userAgent类型:%@ \n值: %@", [userAgent class],userAgent);
    }
}

@end

UIWebView 执行js代码

//得到整个网页源码
NSString *htmlSource = @"document.getElementsByTagName('html')[0].innerHTML;";
        NSString *retHtmlSource = [self.wv stringByEvaluatingJavaScriptFromString:htmlSource];

//ById
NSString *js = @"document.getElementById('scd_num').innerHTML;";
        NSString *retStr = [self.wv stringByEvaluatingJavaScriptFromString:js];

//ByClassName
NSString *js = @"document.getElementsByClassName('results')[0].innerHTML;";
            NSString *retStr = [self.wv stringByEvaluatingJavaScriptFromString:js];
            
// 直接调用js函数
[self.wv stringByEvaluatingJavaScriptFromString:@"函数名('参数1, 参数2');"];  

参考资料:
http://blog.csdn.net/woaifen3344/article/details/42742893