变量已经定义

Question

sometime i need to replace a variable value to another

so i use this method

var $$test = "First",
    $$test = "Second";

the code work fine but i use jsfiddle JSHint button to check any error on JavaScript (it helped me a lot)

but i got this error '$$test' is already defined

so what is the ideal method to re define any variable

Thank you :)

Answer 1

You're getting that error because you're declaring the same variable twice.

var a = foo, a = bar;

Is the same as:

var a = foo;
var a = bar;

Just break your code in two lines, and you won't get that warning. Like this:

var a = foo;
a = bar;

Also notice that if you declare a variable with a value, and then right after that you change its value, the first line is a noop .

Answer 2

Don't use a comma. You should redefine it as a new statement:

var $$test = 'First';
$$test = 'Second';

Answer 3

this code is trying to define two variable s called $$test. They need to have uniuque names. Try using $$test1 and $$test2

updated for you http://jsfiddle.net/9CdJN/2/

(function($){

var $$test = "First";
 $$test = "Second";

console.log($$test);

})(jQuery);

Answer 4

The problem is that you have a comma , at the end of the first line instead of a semi-colon ; .

Each Javascript statement ends with a semi-colon. You can define multiple variables with a single var by separating them all with a comma.

var var1=1, var2=2, var3=3;

is the same as

var var1=1,
    var2=2,
    var3=3;

Because you had a comma in the first line, the browser believes you are declaring two different variables with the same name. To fix it, just change it to this:

var $$test = "First";
    $$test = "Second";