JavaScript null check

Question

I\'ve come across the following code:

function test(data) {
    if (data != null && data !== undefined) {
        // some code here
    }
}
         


        

Answer 1

var a;
alert(a); //Value is undefined

var b = "Volvo"; 
alert(b); //Value is Volvo

var c = null;
alert(c); //Value is null