javascript - How to get the variable value in the variable in the function from the outside

Question

How to get the variable value inside the function from outside the function?

function time(){
      var date＝''2017'';
}
alert(date);

Answer 1

Define global variables, write variable declarations outside the function, and use them directly inside the function

var data;
function time(){
    data="2017";
}
alert(data)

Answer 2

Just return it and it will be fine

Answer 3

It is recommended that the questioner read the relevant knowledge about the scope of variables, which may be of great help.

Answer 4

localStorage

Answer 5

var time = function(){
    this._date = '2017';
}
var fn = new time;
console.info(fn._date);