Introduction to JavaScript

In the HTML position has three blocks: 1.head inside 2.body inside 3.

3 common dialog boxes

Alert () Warning dialog box, which is the function of a warning dialog to pop up.

Confirm () Determines the dialog box, the function is to pop up a selection of OK dialog box, after clicking OK, it returns True, click Cancel to return flase, available variables to accept.

The prompt () function pops up a dialog box that allows you to enter content.

JavaScript syntax

JavaScript: There is only one variable type, var. Data type: Integer, Decimal, String, Boolean

1. How to turn a numeric string into a digital type:
parseint ("string")--turns the string into an integral type
Parsefloat ("string")--turns the string into a decimal number
2. How can I tell if a variable is a number?
var a = IsNaN (b);

True is not a number

False is a number

Array new Array (); its length is dynamically variable, it can be placed in any type of element.

Sorted array: A.sort (); Sort by first character, A.reverse (); Flip Array.

Function

Define function functions Add (formal parameter) {function Body}, functions name Add, input as parameter, return value can be var type or return value.

Function not called does not execute, call of function: Add (argument)

DOM Operations

-blank is a new window open

-slef is its own window open

Introduction to JavaScript