Question

var a = new array();
a[1] = ‘A’;
b[10] = ‘B’;
console.log(a);
/[undefined, “A”, undefined, undefined, undefined, undefined, undefined, undefined,
undefined, undefined, “B”]/
I want to remove undefined element
but what is the process??

Answer 1

First of all, jQuery has nothing to do with this.

Second, arrays are “autofilled”. If you define index 10, all indexes 0 – 9 will be occupied automatically, that’s just the way Javascript arrays work.

What you’re looking for is probably an object:

var a = {};
a[1] = 'A';
a[10] = 'B';

or

var a = {
    1 : 'A',
    10 : 'B'
};