var numeric = [
    ['input1','input2'],
    ['input3','input4']
];
numeric[0][0] == 'input1';
numeric[0][1] == 'input2';
numeric[1][0] == 'input3';
numeric[1][1] == 'input4';
var obj = {
    'row1' : {
        'key1' : 'input1',
        'key2' : 'input2'
    },
    'row2' : {
        'key3' : 'input3',
        'key4' : 'input4'
    }
};
obj.row1.key1 == 'input1';
obj.row1.key2 == 'input2';
obj.row2.key1 == 'input3';
obj.row2.key2 == 'input4';
var mixed = {
    'row1' : ['input1', 'inpu2'],
    'row2' : ['input3', 'input4']
};
mixed.row1[0] == 'input1';
mixed.row1[1] == 'input2';
mixed.row2[0] == 'input3';
mixed.row2[1] == 'input4';
http://jsfiddle.net/z4Un3/
And if you're wanting to store DOM elements:
var inputs = [
    [
        document.createElement('input'),
        document.createElement('input')
    ],
    [
        document.createElement('input'),
        document.createElement('input')
    ]
];
inputs[0][0].id = 'input1';
inputs[0][1].id = 'input2';
inputs[1][0].id = 'input3';
inputs[1][1].id = 'input4';
Not real sure how useful the above is until you attach the elements. The below may be more what you're looking for:
<input text="text" id="input5"/>
<input text="text" id="input6"/>
<input text="text" id="input7"/>
<input text="text" id="input8"/>    
var els = [
    [
        document.getElementById('input5'),
        document.getElementById('input6')
    ],
    [
        document.getElementById('input7'),
        document.getElementById('input8')
    ]
];    
els[0][0].id = 'input5';
els[0][1].id = 'input6';
els[1][0].id = 'input7';
els[1][1].id = 'input8';
http://jsfiddle.net/z4Un3/3/
Or, maybe this:
<input text="text" value="4" id="input5"/>
<input text="text" value="4" id="input6"/>
<br/>
<input text="text" value="2" id="input7"/>
<input text="text" value="4" id="input8"/>
var els = [
    [
        document.getElementById('input5'),
        document.getElementById('input6')
    ],
    [
        document.getElementById('input7'),
        document.getElementById('input8')
    ]
];
var result = [];
for (var i = 0; i < els.length; i++) {
    result[result.length] = els[0][i].value - els[1][i].value;
}
Which gives:
[2, 0]
In the console. If you want to output that to text, you can result.join(' ');, which would give you 2 0.
http://jsfiddle.net/z4Un3/6/
EDIT
And a working demonstration:
<input text="text" value="4" id="input5"/>
<input text="text" value="4" id="input6"/>
<br/>
<input text="text" value="2" id="input7"/>
<input text="text" value="4" id="input8"/>
<br/>
<input type="button" value="Add" onclick="add()"/>
// This would just go in a script block in the head
function add() {
    var els = [
        [
            document.getElementById('input5'),
            document.getElementById('input6')
        ],
        [
            document.getElementById('input7'),
            document.getElementById('input8')
        ]
    ];
    var result = [];
    for (var i = 0; i < els.length; i++) {
        result[result.length] = parseInt(els[0][i].value) - parseInt(els[1][i].value);
    }
    alert(result.join(' '));
}
http://jsfiddle.net/z4Un3/8/