for storing value in a Array we have to declare a special Variable (array) like (var array_name = ;) and inside the box brackets  we have to write values for our Special Variable. We can assign numeric and String values to our Special Variable (array) and separate multiple values using single , comma.
var myArray = ["value1","value2","value3"];
we can assign multiple value to a single Variable in array and for calling array Values we have to write our Array Variable name and this will export the all Array Values bu if we want to export only one array Value then we have to write array name first and then index number of the assigned value.
Array index number starts from 0 and ends according to total number of assigned values in array.
example : var my_array = ["cat","dog","cow","rat"];
var my_array = [0,1,2,3];
here at the index 0 we have cat,
index 1 we have dog,
at index 2 we have cow,
and at index 3 we have rat.
var myArray = ["cat","dog","cow","rat"]; document.write(myArray);
There is a another easy and more understandable way to assign value to Array by using Index number, As we know array's index starts from 0 so the first value will have the index number of 0 and by using this method we can easily identify values bu Index numbers.
to do that we have to define a empty array like var myArray = ;
and after terminating ; the declaration line we can assign values by variable name with index numbers like myArray ="";.
var myArray = ; myArray="cat"; myArray="dog"; myArray="cow"; myArray="rat"; document.write(myArray);
to assign new value to JS Array we have to write our array name with .push method and inside the round brackets/braces we have to write new value for our Array.
var myArray=["cat","dog","rat"]; myArray.push("cow"); document.write(myArray);
var myArray = ; myArray["firstValue"]="cat"; myArray["secondValue"]="dog"; myArray["thirdValue"]="cow"; document.write(myArray["thirdValue"]);