Answers for "Write a javascript function named is_integer which checks if the passed argument is an integer. You can use any mathematical operator or functions defined in the Math object."

javascript check if a value is an int

// The Number.isInteger() checks to see if the passed value is an integer
// Returns true or false

Number.isInteger(2); //True
Number.isInteger(90); //True
Number.isInteger("37"); //False
Number.isInteger(false); //false

js is variable int

// The === operator is used for checking
// the value and the type of a variable

var data = 1;

if (data === parseInt(data, 10))
    alert("data is integer")
else
    alert("data is not an integer")