Ajax1-php (27), ajax1php2

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