Creating a multidimensional array in javascript

I know that javascript does not allow true multidimensional arrays, but you can sort "bodge" together by having arrays inside arrays.

I have 2 questions:

1) Will the conversion of 10 arrays into one multidimensional array, which has 10 arrays in it, improve, damage or not affect the performance of the web page?

2) I hope to create an array containing 100 elements, each of which will be an array of two elements, and finally, each of them will be an array of indefinite length.

I have the following code to create this "multidimensional" array:

var RouteArray = new Array(100);
for (var i=0; i <100; i++)
{
RouteArray[i]=new Array(2);
    for (var j=0; j <2; j++)
    {
    RouteArray[i][j] = new Array();
    }
}

Is this code reasonable? or would you experienced coders offer a better method?

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RouteArray[88][0].push(ValueToPush);

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Var ValueAdded = RouteArray[88][0][0];

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