defining multiple variables with one `var` keyword in javascript [duplicate]

问题

This question already has answers here:

Declaring multiple variables in JavaScript (17 answers)

Closed 4 years ago.

I have a line in my source code written by someone else:

var campaignLimits = 10, campaignsArray = new Array();

I just wanted to know, whether campaignsArray here becomes global variable, or the var applies to campaignsArray as well?

回答1:

Assuming you have not used any programming pattern, If its written inside a function then its not global.

(function() { var campaignLimits = 10, campaignsArray = new Array(); })();

as @phoa commented it is same as

(function() { var campaignLimits = 10; var campaignsArray = new Array(); })();

Try it in your console and see whether you will be able to access campaignsArray.

来源：https://stackoverflow.com/questions/40883472/defining-multiple-variables-with-one-var-keyword-in-javascript