apply

<script>

window.firstName = "zst"; 

window.lastName = "tao"; 

var myObject = { firstName: "my", lastName: "Object" }; 

function Hello() { 

var testStr = "Hello " + this.firstName + " " + this.lastName;

alert(testStr);

console.log("Hello " + this.firstName + " " + this.lastName); 

}

Hello.apply(window);

Hello.apply(myObject);

</script>