Array Object The Array object is used to store multiple values in a single variable: var cars = [“Saab”, “Volvo”, “BMW”]; Array indexes are zero-based: The first element in the array is 0, the second is 1, and so on. For a tutorial about Arrays, read our JavaScript Array Tutorial. Array Properties Property Description constructor Returns the function that […]
Method Reuse With the call() method, you can write a method that can be used on different objects. All Functions are Methods In JavaScript all functions are object methods. If a function is not a method of a JavaScript object, it is a function of the global object (see previous chapter). The example below creates an […]
The code inside a JavaScript function will execute when “something” invokes it. Invoking a JavaScript Function The code inside a function is not executed when the function is defined. The code inside a function is executed when the function is invoked. It is common to use the term “call a function” instead of “invoke a function“. It […]
JavaScript functions are defined with the function keyword. You can use a function declaration or a function expression. Function Declarations Earlier in this tutorial, you learned that functions are declared with the following syntax: function functionName(parameters) { code to be executed } Declared functions are not executed immediately. They are “saved for later use”, and will be executed later, when they are invoked (called upon). […]
A JavaScript function does not perform any checking on parameter values (arguments). Function Parameters and Arguments Earlier in this tutorial, you learned that functions can have parameters: functionName(parameter1, parameter2, parameter3) { code to be executed } Function parameters are the names listed in the function definition. Function arguments are the real values passed to (and received by) the function. Parameter Rules JavaScript function definitions […]
Hoisting is JavaScript’s default behavior of moving declarations to the top. JavaScript Declarations are Hoisted In JavaScript, a variable can be declared after it has been used. In other words; a variable can be used before it has been declared. Example 1 gives the same result as Example 2: Example 1 x = 5; // Assign 5 to x […]
A JavaScript function is a block of code designed to perform a particular task. A JavaScript function is executed when “something” invokes it (calls it). Example function myFunction(p1, p2) { return p1 * p2; // The function returns the product of p1 and p2 } Try it Yourself » JavaScript Function Syntax A JavaScript function is defined […]
