var person = {"first_name": "Billy","last_name": "Johnson"}; delete person.last_name; //delete last_name property
var person = { name: "Harry", age: 16, gender: "Male" }; // Deleting a property completely delete person.age; alert(person.age); // Outputs: undefined console.log(person); // Prints: {name: "Harry", gender: "Male"}
var string = "Hello World"; var substring = "Hello"; if (string.indexOf(substring) != -1) { //Code here }