var a = new Array(5); var b = [undefined,undefined,undefined,undefined,undefined]; console.log("a[0]: " + a[0]); console.log("b[0]: " + b[0]); console.log("a[4]: " + a[4]); console.log("b[4]: " + b[4]); console.log("b[2]===a[2]: " + (b[2]===a[2])); console.log("a===b: " + (a===b)); console.log("a==b: "+ (a==b)); a.map(function() { console.log("Hallo from a array") }); b.map(function() { console.log("Hallo from b array") });