when using javascript objects, you can also just use "dot notation" to add an item, (which JSLint prefers)
var myArray = { name : "john" };
//will initiate a key-value array with one item "name" and the value "john"
myArray.lastName = "smith";
//will add a key named lastName with the value "smith"
//Object {name: "john", lastName: "smith"}
Here is a screenshot from testing in the Chrome console