Detailed explanation of PHP+Ajax username detection_PHP tutorial

This example requires a total of 3 files

Ajax.js

var xmlHttp;

//Instantiation process

function S_xmlhttprequest(){

if(window.ActiveXObject){

xmlHttp=new ActiveXObject('Microsoft.XMLHTTP');

}else if(window.XMLHttpRequest){

xmlHttp=new XMLHttpRequest();

}

}

function funphp100(name){

//Get form content

//http://www.ruoshuiyx.com Shenyang website construction

var f=document.myform.user.value;

//Reference instantiation process

S_xmlhttprequest();

//Open request

xmlHttp.open("GET","index.php?id="+f,true);

//Ready to execute

xmlHttp.onreadystatechange=byphp;

xmlHttp.send(null);

}

function byphp() {

if(xmlHttp.readyState== 1) {

document.getElementById('php100').innerHTML = "";

}

if(xmlHttp.readyState== 4){

if(xmlHttp.status == 200) {

var byphp100 = xmlHttp.responseText;

document.getElementById('php100').innerHTML = byphp100;

}

}

}

For.php

Username//http://www.ruoshuiyx.com Shenyang website construction:

Index.php

if($id=$_REQUEST[id])

{

//for ($i=1;$i

//{

// echo$id;

// sleep(1);//

//}

sleep(2);

if($id=='4125')

{

echo "already exists";

}

else

{

echo "Can register";

}

//exit();

}

?>

Knowledge points:

1. Principle of user name checking implemented by Ajax technology

2. Several triggers for learning HTML

The onblur event occurs when an object loses focus.

The onchange event occurs when the content of the field changes.

The onclick event occurs when the object is clicked.

The onfocus event occurs when an object gains focus.

The onkeydown event occurs when the user presses a keyboard key.

The onkeypress event occurs when a keyboard key is pressed and a key is released.

The onkeyup event occurs when a keyboard key is released.

The onmousedown event occurs when the mouse button is pressed.

The onmousemove event occurs when the mouse pointer moves.

The onmouseout event occurs when the mouse pointer moves out of the specified object.

The onmouseup event occurs when the mouse button is released.

3. How to get the data content in the form

document.myform.user.value

http://www.bkjia.com/PHPjc/477696.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/477696.htmlTechArticleThis example requires a total of 3 files Ajax.js var xmlHttp; //instantiation process function S_xmlhttprequest(){ if (window.ActiveXObject){ xmlHttp=new ActiveXObject(Microsoft.XMLHTTP); }else if(window...