iOS:在OC中调用JS脚本

示例一：在webView中调用js脚本进行搜索

1.首先导入JavaScriptCore.framework这个框架

2.创建webView、设置代理、请求手机端百度

#import "ViewController.h"

#import <JavaScriptCore/JavaScriptCore.h>

#define SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width

#define SCREEN_HEIGHT [UIScreen mainScreen].bounds.size.height

@interface ViewController ()<UIWebViewDelegate>

@property (strong,nonatomic)UIWebView *webView;

@property (assign,nonatomic)BOOL isFirstLoadWeb;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    self.webView = [[UIWebView alloc]initWithFrame:self.view.bounds];

    self.webView.scalesPageToFit = YES;

    self.webView.backgroundColor = [UIColor clearColor];

    self.webView.delegate = self;

    [self.view addSubview:self.webView];

    NSURL *URL = [NSURL URLWithString:@"http://m.baidu.com"];

    NSURLRequest *request = [[NSURLRequest alloc]initWithURL:URL];

    [self.webView loadRequest:request];

}

3.通过代理方法,在里面调用自定义的JS脚本

-(void)webViewDidFinishLoad:(UIWebView *)webView{

    //程序会一直调用该方法,所以判断若是第一次加载后使用我们自定义的js,此后不再调用JS,否则会出现网页抖动现象

    if (!_isFirstLoadWeb) {

        _isFirstLoadWeb = YES;

        //获取当前页面的url

        NSString *url = [webView  stringByEvaluatingJavaScriptFromString:@"document.location.href"];

        //获取页面的title

        NSString *title = [webView stringByEvaluatingJavaScriptFromString:@"document.title"];

        NSLog(@"%@----%@",url,title);

        //给webView添加一个自定义的JavaScript

        [webView stringByEvaluatingJavaScriptFromString:@"var script = document.createElement('script');"

            "script.type = 'text/javascript';"

            "script.text = \"function myFuncation(){"

            "var field = document.getElementsByName('word')[0];"

            "field.value = '夏先森的博客园';"

            "document.forms[0].submit();"

         "}\";"

         "document.getElementsByTagName('head')[0].appendChild(script);"];

        //开始调用自定义的JavaScript

        [webView stringByEvaluatingJavaScriptFromString:@"myFuncation();"];

    }else{

        return;

    }

}

@end

演示截图如下：

-- ::24.670 OC调用JS[:] https://m.baidu.com/----百度一下

  

示例二：通过滑动条动态改变网页中字体的大小

1.首先导入JavaScriptCore.framework这个框架

2.创建webView、设置代理、请求手机端百度

#import "ViewController.h"

#import <JavaScriptCore/JavaScriptCore.h>

#define SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width

#define SCREEN_HEIGHT [UIScreen mainScreen].bounds.size.height

@interface ViewController ()<UIWebViewDelegate>

@property (strong,nonatomic)UIWebView *webView;

@property (strong,nonatomic)UIActivityIndicatorView *activityIndicator;

@property (strong,nonatomic)UISlider *slider;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    //1.创建slider

    _slider = [[UISlider alloc]initWithFrame:CGRectMake(, , SCREEN_WIDTH-, )];

    [_slider addTarget:self action:@selector(SliderChanged) forControlEvents:UIControlEventValueChanged];

    _slider.maximumValue = 1000.0f;

    _slider.minimumValue = 10.0f;

    _slider.value = 10.0f;

    [self.view addSubview:_slider];

    //2.创建webView

    self.webView = [[UIWebView alloc]initWithFrame:CGRectMake(, , SCREEN_WIDTH, SCREEN_HEIGHT-)];

    self.webView.scalesPageToFit = YES;

    self.webView.backgroundColor = [UIColor clearColor];

    self.webView.delegate = self;

    [self.view addSubview:self.webView];

    NSURL *URL = [NSURL URLWithString:@"http://m.baidu.com"];

    NSURLRequest *request = [[NSURLRequest alloc]initWithURL:URL];

    [self.webView loadRequest:request];

    //3.创建活动指示器

    _activityIndicator = [[UIActivityIndicatorView alloc]initWithFrame:CGRectMake(, , , )];

    _activityIndicator.center = self.view.center;

    _activityIndicator.backgroundColor = [UIColor grayColor];

    _activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;

    [self.view addSubview:_activityIndicator];

}

3.滑动滑动条来改变网页字体大小

-(void)SliderChanged{

    NSString *str1 = [NSString stringWithFormat:@"document.getElementsByTagName('body')[0].style.webkitTextSizeAdjust = '%f%%'",_slider.value];

    [_webView stringByEvaluatingJavaScriptFromString:str1];

}

@end

演示截图如下：