如何在javascript回调函数中传递全局变量？

Question

I want to pass a global variable to a javascript .each function and keep its value while the iteration.

Here is the code.

 var year = false;
 page.posts.each(function(item, year){
   year = true;
 });

The year is still false. How can year keeps its value in the iteration?

Answer 1

You have a name conflict between the function parameter and the global variable. As the function parameter name is closer to the executed code, when JavaScript looks up through the variable names to find out what you meant, it finds the parameter name first, so that is what becomes set.

If you want to explicitly set the global variable, you'll have to access it though window , ie

window.year = true; // explicit global

Answer 2

There is a conflict in your variable names.

var year = false;
 page.posts.each(function(item, yr){
   year = true;
 });

Answer 3

Try attaching to window document and see.

 window.year = false;
 page.posts.each(function(item, year){
   year = true;
 });

Answer 4

you can rename variable year to avoid conflict, or if you just want to change global variable , you should use window.year = true

page.posts.each(function(item, year){
   year = true;  
});