[Rise]

var rows = map.length, columns = map[0].length;
var marioRow = 0, marioColumn = 0;

document.onkeydown = function (event) {
    if (event.keyCode == 37) {
        if (marioColumn > 0) marioColumn--;
    } else if (event.keyCode == 38) {
        if (marioRow > 0) marioRow--;
    } else if (event.keyCode == 39) {
        if (marioColumn < columns - 1) marioColumn++;
    } else if (event.keyCode == 40) {
        if (marioRow < rows - 1) marioRow++;
    }
    cellList[marioRow][marioColumn].appendChild(mario);
}