利用JavaScriptCore实现以下简单的功能（平方和）

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

 @interface RootViewController ()<UIWebViewDelegate>
 @end

 @implementation RootViewController

 - (void)viewDidLoad {
     [super viewDidLoad];

     JSContext *context = [[JSContext alloc] init];
     [context evaluateScript:@"var square = function(x){return x*x;}"];
     JSValue *squareFunction = context[@"square"];
     JSValue *nineSquared = [squareFunction callWithArguments:@[@]];
     NSLog(@"9^2:%@",nineSquared);

 }

 @end