Sorting in Javascript Action

I have captured all values to json which is like this:
captured_json=["2.13","1.212","1.313","13.23","20.666"]
when i try to use sort function in java script action like below:
captured_json.sort()
its throwing me an error cant find function sort in object .
I have to find an highest element in an array by sorting from highest to lowest or viceversa here in my case my desired output should be like below:
input: ["2.13","1.212","1.313","13.23","20.666"]
Desired output: ["1.212","1.313","2.13","13.23","20.666"]