Create a table with value from checkboxes

I have this question in my assignment:

Show the elements number and value of the six checkboxes in a six-row, two-column table with a 2 pixel border in the span block with id="ans18"

This is what I have so far:

o = "<table border = 2>";
for(i = 5; i <= 10; i++)
    {
    o += "<tr>";
    for(j = 0; j < 1; j++)
        {
        o += "<td>" + document.alice.element[i] + "</td>" + "<td>" + i + "</td>";
        }
    o += "</tr>";   
    }
o += "</table>";
ans18.innerHTML = o;

The checkboxes that I have to look at have the names c1-c6, with elements 5-10 and values of "K","M","O","C","L","T" in that order.

I know problem with my code is this line

o += "<td>" + document.alice.element[i] + "</td>" + "<td>" + i + "</td>";

I just don't know why.Please help! Also, it has to be in JavaScript