Get started with AJAX

Overview: AJAX uses HTML javascript™DHTML is composed of DOM components. The effect is to make the dull web form into a more interactive AJAX form.

Focus, master core creation components, etc.

I. Core creation components

XmlHttp = new XMLHttpRequest (); unfortunately, Microsoft's IE does not support this method.

XmlHttp = new ActiveXObject ('Microsoft. xmlhttp'); Microsoft can only use this method

So in general, we need to make a judgment.

Var xmlHttp; function A_xmlHttpRequest () {if (window. activeXObject) {xmlHttp = new ActiveXObject ('Microsoft. HTTP ');} else if (window. XMLHttpRequest) {xmlHttp = new XMLHttpRequest;} 2. Use the method declaration to open the request and obtain the execution result.

1. method declaration

XmlHttp. open ('transfer method ', 'address', whether asynchronous transmission is allowed)

XmlHttp. open ("GET", "for. php? Id = "+ url, true );

2. Open Request status

XmlHttp. onreadystatechange = method name

XmlHttp. onreadystatechange = byphp;

3. Get execution results

Var result name = xmlHttp. responseText

Var byphp100 = xmlHttp. responseText;

Example 1: Create a preliminary AJAX Program

Xunhuan. php

<? $ Id = $ _ GET [id]; if ($ id) {for ($ I = 0; $ I <10; $ I ++) {echo $ id ;}}?> Ajax.html

<! DOCTYPE html PUBLIC "-// W3C // dtd xhtml 1.0 Transitional // EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

Var xmlHttp; function A_xmlHttpRequest () {if (window. activeXObject) {xmlHttp = new ActiveXObject ('Microsoft. XMLHTTP ');} if (window. XMLHttpRequest) {xmlHttp = new XMLHttpRequest () ;}} function funphp100 (url) {A_xmlHttpRequest (); xmlHttp. open ('get', 'xunhuan. php? Id = '+ url, true); xmlHttp. onreadystatechange = byphp; xmlHttp. send (null);} function byphp () {var byphp100 = xmlHttp. responseText; document. getElementById ('php100 '). innerHTML = byphp100 ;}

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