JavaScript array (array) method of using string as array subscript

Array is inherited from Object. It has all the functions and features of Object. Here is the situation of Object:
Create: var object = new Object();
Added: object[strIndex] = value; (strIndex is string)
Delete: delete object[strIndex];
Traversal: for ( var strObjIndex in object ) object[strObjIndex ];
as follows:

Copy the codeThe code is as follows:

var obj = new Object();
    obj["first"] = "my";
    obj["second"] = "name";
    obj["third"] = "is";
    obj["fourth"] = "chenssy";

Because Array inherits Object, Array can also use strings as array subscripts:
as follows

Copy the codeThe code is as follows:

var array = new Array();
    array["first"] = "my";
    array["second"] = "name";
    array["third"] = "is";
    array["fourth"] = "chenssy";

For the traversal of array numbers, we use the for loop statement. But this for loop is not in this form:

Copy the codeThe code is as follows:

for(int i = 0;i<;i++)

We can use the for/in loop to traverse the array. The for/in loop temporarily assigns the subscript of an array to a variable:

Copy the codeThe code is as follows:

1for(variable in array)

In the first loop, the variable variable will be assigned to the subscript value of the first element of the array array; in the second loop, the variable variable will be assigned to the subscript value of the second element of the array array; and so on...
For the above array array, use for/in to loop through:

Copy the codeThe code is as follows:

for(key in array)