html-Lesson Plan-javascript Introduction

First,JavaScript Introduction

What's a 1.JavaScript thing?

It is a scripting language and requires a host file whose host file is an HTML file.

2. What does it have to do with Java ?

There is no direct connection,Java is the Sun Company (has been acquired by Oracle ),JavaScript is a Netspace (Netscape, which has been acquired by AOL), JScript It's Microsoft's, 90% like JavaScript , some features can only be IE used on.

3. its usage:

There are three blocks in the HTML position:

(1) inside head

(2)body inside

(3) after

For insurance purposes, it is generally written after .

<script language= "JavaScript" > code must be placed in this area </script>

4. three common dialog boxes:

　　alert ("") A warning dialog box that pops up a warning dialog box.

　　confirm ("") determines the dialog box, the function is to pop up a selection of OK dialog box, after clicking OK, it returns ture , click Cancel to return false , you can use variables to receive them.

　　prompt (" hint text to display "), the function is to pop up a dialog box that allows you to enter content.

Second,JavaScript Syntax

1. Basic data type:

String, Decimal, Integer, DateTime, Boolean, and so on.

2. variables:

are generic type var, can store other types of values, can be used directly, not defined. But it's customary to define.

Defining variables: var A; all variable definitions are defined by var andvar is a generic mutable type.

var s = "3.14"; var n = parsefloat (s);; s + = 5;
var d = parseint (s);

3. Arrays:

Definition of the array:new Array (); Its length is dynamically variable and can be placed in any type of element.

Assignment of array elements:a[0]=123; a[1]= "Hello"; The index in the element starts at 0 .

The value of the array:a[i];

Array properties:a.length; the number and length of array elements.

Methods:A.sort ();// array Sorting, sorted by the first character of each element.   a.reverse (); flips the array.

4. functions:

Four elements of a function: name, input, return value, processing.

Define functions: FunctionAdd ( formal parameter ) { function body }// function named add, input as Parameter form , the return value can be either a var type or a return value.

The function must be called to execute. Call to function:add(argument).

* can be read on the head (first read the head)

The page is automatically refreshed when the form is submitted, preferably turned off

Writing:

1. Output

<script>

document.write ("Hello World");

</script>

2. Button Application

<input name= "alert" value= "alert" type= "button" onclick= ' Alert (" This is the trigger event ") '/>

3. Define variables and output

　　　var Bianliang;

Bianliang= "123";

document.write (Bianliang);

4. Changing the attributes of an element

<p id= "Hello" >hello</p>

<script>

function Hello ()

{

X=document.getelementbyid ("Hello")

X.style.color = "#ff0000";

}

</script>

<input type= "button" value= " Click to change color " onclick= "Hello ()"/>

<!-- Click From Black to Red --

5, item index, indicating The nth occurrence of the element, with getelementsbyname simultaneous use

Define a set of variables

var student =

{

Name: " Zhang San ",

Sex: " male "

};

Student.name= " Zhang San ";

document.write (Student.name);

(* print " Zhang San ")

External call JS

<script src= "" ></script>

html-Lesson Plan-javascript Introduction