How can I create an array from this table/form? The onclick function formData() from the dynamic table only returns a concatenated string. I need to create an associative array in JSON using the 'device' variable as key, however I'll settle for any sort of array at all. Clearly, I'm not very good at this...

```js
function createInputTable() 
    {
    var num_rows = document.getElementById('rows').value;
    var tableName = document.getElementById('conn_input_device').value;
    var column_number = 2;
    var tdefine = '<form id="form"><table id="table" border = "1">\n';
    var theader = '<tr><th>No</th><th>Input</th><th>Output</th></tr>\n';
    var caption = '<caption><input id="device" value ="' + tableName + '" /></caption>';
    var tbody = '';
    var tfooter = '</table>';
    var createNewDevice = '<button onclick="formData();">Form Data</button></form>'
    var i = 0;                  

    for (var i= 0; i < num_rows; i++)
      {
      tbody += '<tr><td>' + (i+1)  + '</td><td><input class="cell" id="i'+ i + '" type = "text"/></td>';
      tbody += '<td><input class="cell" id="o'+ i + '" type="text"/></td></tr>\n';
      }
      document.getElementById('wrapper').innerHTML = caption + tdefine + theader + tbody + tfooter + createNewDevice;

    }

    function formData()
    {
        var cellData = document.getElementById("form");
        //var device = document.getElementById('device').value;
        //var j;
        var obj = [];
        for(j=0; j< cellData.length; j++)
        {
            obj += cellData[j].value;
        }
        var json = JSON.stringify(obj);
        alert (json);
        //document.getElementById('result').innerHTML = json;
    }
```

```html
    <form id="tableGen" name="table_gen">
        <label>Connecting device: <input type = "text" name = "conn_input_device" id = "conn_input_device"/></label><br />
        <label>Number of inputs: <input type="text" name="rows" id="rows"/></label><br />
        <input name="generate" type="button" value="Create Input Table!" onclick='createInputTable();'/>
    </form>

    <div id="wrapper"></div>
```