what is the use of parseInt code example

Example 1: parseint javascript

var myInt = parseInt("10.256"); //10
var myFloat = parseFloat("10.256"); //10.256

Example 2: parseint method

parseInt("10");         // returns 10

parseInt("10.33");      // returns 10

parseInt("10 20 30");   // returns 10

parseInt("10 years");   // returns 10
parseInt("years 10");   // returns NaN