显示数组中文本的随机值

Question

I have the following:

var movie;

var myMovies = ['Bones', 'Psych', 'Big Bang Theory', 'Mad Men', 
'Breaking Bad', 'Modern Family', 'Game of Thrones', 'Dexter','Bones', 'Psych', 'Big Bang Theory', 'Mad Men', 
'Breaking Bad', 'Modern Family', 'Game of Thrones', 'Dexter','Bones', 'Psych', 'Big Bang Theory', 'Mad Men', 
'Breaking Bad', 'Modern Family', 'Game of Thrones', 'Dexter'];

function generateMovies () {
  var movie = myMovies[Math.floor(Math.random() * myMovies.length)];
}


function displayMovie() {
  generateMovies();
  console.log(movie);
  $('body').text(movie);

  setTimeout(function(){
    displayMovie();
},1000);
}

displayMovie();

I would like to generate a different movie name and show them on the screen. Seems to be straight forward but obviously not! Seems like may variable is undefined.

Thanks!

Fiddle: https://jsfiddle.net/4ggwva4f/8/

Answer 1

您在函数内部声明了变量movie，因此没有将值分配给全局变量。

Answer 2

Just remove var in your generateMovies function.

function generateMovies () {
  movie = myMovies[Math.floor(Math.random() * myMovies.length)];
}

Basically, you're declaring movie first at the start of your script, then again within your generateMovies function, so movies is not being returned into your global scope.

Answer 3

As the other guys mentioned, you have a scope problem. Also, you don't really need the global movie variable, you could change your code to return the expected value like this:

var myMovies = ['Bones', 'Psych', 'Big Bang Theory', 'Mad Men', 
'Breaking Bad', 'Modern Family', 'Game of Thrones', 'Dexter','Bones', 'Psych', 'Big Bang Theory', 'Mad Men', 
'Breaking Bad', 'Modern Family', 'Game of Thrones', 'Dexter','Bones', 'Psych', 'Big Bang Theory', 'Mad Men', 
'Breaking Bad', 'Modern Family', 'Game of Thrones', 'Dexter'];

function generateMovies () {
  return myMovies[Math.floor(Math.random() * myMovies.length)];
}

function displayMovie() {
  var movie = generateMovies();
  console.log(movie);
  $('body').text(movie);

  setTimeout(function(){
    displayMovie();
},1000);
}

displayMovie();

Or if you don't really need to do the console.log just: $('body').text(generateMovies())