Issues Stringifying a multidimensional array with json.js

Question

I have problems with .stringify(), but I think my JavaScript array must be wrong, here's my code:

var questions = new Array();

$('#Valid').hover(function(){
    for (i=0;i < $('.Questions').length;i++){
        questions[i]=new Array();
        questions[i]['numero']=$('.Numero:eq('+i+')').html();
        questions[i]['question']=$('.ItemInput:eq('+i+')').val();
        questions[i]['variable']=$('.VarName:eq('+i+')').val();
    }

    var stringJSON=JSON.stringify(questions)
    alert (stringJSON)
})

The stringJSON var returns :

[[]]

What am I doing wrong?

Answer 1

Arrays have integer keys, not strings.

Use an object instead; objects in JS sort of look like associative arrays:

var questions = new Array();
$('#Valid').hover(function(){
    for (var i=0;i < $('.Questions').length;i++){
        questions[i]={};
        questions[i]['numero']=$('.Numero:eq('+i+')').html();
        questions[i]['question']=$('.ItemInput:eq('+i+')').val();
        questions[i]['variable']=$('.VarName:eq('+i+')').val();
    }

    var stringJSON=JSON.stringify(questions);
    alert(stringJSON);
});

Setting questions[i] to {} is the key.

You can shorten this syntax:

var questions = new Array();
$('#Valid').hover(function(){
    for (var i=0;i < $('.Questions').length;i++){
        questions[i] = {
            numero:   $('.Numero:eq('+i+')').html(),
            question: $('.ItemInput:eq('+i+')').val(),
            variable: $('.VarName:eq('+i+')').val()
        };
    }

    var stringJSON=JSON.stringify(questions);
    alert(stringJSON);
});

Answer 2

Fix:

Replace questions[i]=new Array(); with questions[i] = {}; (or = new Object(); if you really want this "ugly" syntax).

Explanation:

Arrays in JavaScript are like arrays in languages like C: They only support integer indexes in the interval [0, array.length).

For associative arrays, you use objects which are created using the object literal {}.