Tutorial for ajax1-php (27), ajax1php27_PHP

Ajax1-php (27), ajax1php2. Ajax1-php (27), ajax1php2 A Brief Introduction to web program working principle diagram: the traditional web program working principle diagram: 2, the core object XMLHttpRequest I, create an object in a different browser ajax1-php (27), ajax1php2

1 Introduction

Working Principle of web programs:

Working Principle of traditional web programs:

II. Core objects

XMLHttpRequest

1. create an object

In different browsers, the method for creating ajax objects is slightly different.

IE:

New ActiveXObject ("Microsoft. XMLHTTP ")

III. Ajax object attributes and methods:

1. related methods:

L open (method, url)

Initialize ajax objects

Method: request method post, get

Url: Request resource address

L setRequestHeader (header, value)

Set request header information

Header: Header information

Value: Value

L send (content)

Send request

Content: The passed parameter must be placed here only when the post request is made.

2. related attributes:

L readyState

The status code of the Ajax object, which changes at any time

0: indicates that the object has been created but not initialized.

1: indicates that the object has been initialized but not sent

2: The send method has been called for the request.

3: receiving data (receiving part)

4: Received

L onreadystatechange

The callback function triggered when the status code of the ajax object changes.

L status

Http response status code

L statusText

Http response text

L responseText

Http response content text

L responseXML

Xml data of http response content

There are three main ways to transmit Ajax object data:

Text: responseText

Xml: reponseXML

Json: responseText

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