“无法在2d数组中读取未定义的属性0”

Question

有谁知道为什么会出错？我一直在尝试这么长时间，我似乎无法弄明白。它错误地“无法读取未定义的属性0”，但它已明确定义。 （或者我认为）

var categorySix = [["test"]["test2"],["testing"]["one"],["two"]["three"]];
document.write(categorySix[0][0]);

Answer 1

var categorySix = [["test","test2"],["testing","one"],["two","three"]];

您的语法已关闭。

Answer 2

您声明2D阵列错误。

试试这个：

var categorySix = [["test","test2"],["testing","one"],["two","three"]];

Answer 3

您没有正确创建阵列。

我认为应该是

var categorySix = [["test","test2"],["testing","one"],["two","three"]];
document.write(categorySix[0][0]);

根据How can I create a two dimensional array in JavaScript?