Question

What is wrong with this line.
it says uncaught syntax error in the console.

 var aqar= new Array(1:'1_2',2:'5_1',3:'3_3');

Answer 1

If you’re really trying to create an array, normally JavaScript arrays are 0-based, not 1-based, and that’s now how you initialize them.

Here’s a zero-based array

var aqar = ['1_2', '5_1', '3_3'];

Or you may prefer to use a non-array object:

var aqar = {
    1: '1_2',
    2: '5_1',
    3: '3_3'
};

…but then you won’t have all the great Array stuff.

If you really want to, you can create a JavaScript array that has no element at position 0 like this:

var aqar = [];
aqar[1] = '1_2';
aqar[2] = '5_1';
aqar[3] = '3_3';

That creates a sparse array (an array with holes in it). It has no element 0. (As opposed to having an element 0 with the value null, which is what another answer here does.) But unless you have a very good reason, I wouldn’t.