javascript-in_and_hasOwnProperty

2019-12-04

javascript

Javascript ‘in’ and ‘object.hasOwnProperty’

var book = {
    title: "High Performance JavaScript",
    publisher: "Yahoo! Press" 
};

alert(book.hasOwnProperty("title"));  //true
alert(book.hasOwnProperty("toString"));  //false
alert("title" in book); //true 
alert("toString" in book); //true

1	var book = {
2	title: "High Performance JavaScript",
3	publisher: "Yahoo! Press"
4	};
5
6	alert(book.hasOwnProperty("title")); //true
7	alert(book.hasOwnProperty("toString")); //false
8	alert("title" in book); //true
9	alert("toString" in book); //true