Javascript - How to get string element from json object : I have a variable that defines the integer.

Example:

    var integer = x //11111, 222222, 333333, etc.

Then, I have a JSON object:   

    Object { 111111: "string1", 222222: "string2", 333333: "string3", etc }

How to get a specific string element based on the integer variable I have?

Example:
If Selected Variable `22222` is how to get `string2`?