PHP Beginner's Introduction to AJAX and PHP
1. AJAX is used to create more interactive applications
2.ajax php Example
The following example will demonstrate when the user enters the input box How does the web page communicate with the Web server when characters are typed in
<!DOCTYPE html>
<html>
<meta charset="utf-8">
<head>
<script>
function showHint(str){
if (str.length==0){
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest){
// IE7+, Firefox, Chrome, Opera, Safari 瀏覽器執(zhí)行的代碼
xmlhttp=new XMLHttpRequest();
}else{
//IE6, IE5 瀏覽器執(zhí)行的代碼
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState==4 && xmlhttp.status==200){
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","gethint.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<p><b>在輸入框中輸入一個姓名:</b></p>
<form>
姓名: <input type="text" onkeyup="showHint(this.value)">
</form>
<p>返回值: <span id="txtHint"></span></p>
</body>
</html>If the input box is empty (str.length==0), this function will clear the content of the txtHint placeholder and exit the function.
If the input box is not empty, then showHint() will perform the following steps:
Create an XMLHttpRequest object
Create a function that is executed when the server response is ready
Send a request to the file on the server
Please pay attention to the parameter (q) added to the end of the URL (contains the content of the input box)
PHP file
The above paragraph The server page called via JavaScript is a PHP file named "gethint.php".
The source code in "gethint.php" will check the name array and then return the corresponding name to the browser:
gethint.php source code is as follows:
<?php
// 將姓名填充到數(shù)組中
$a[]="Anna";
$a[]="Brittany";
$a[]="Cinderella";
$a[]="Diana";
$a[]="Eva";
$a[]="Fiona";
$a[]="Gunda";
$a[]="Hege";
$a[]="Inga";
$a[]="Johanna";
$a[]="Kitty";
$a[]="Linda";
$a[]="Nina";
$a[]="Ophelia";
$a[]="Petunia";
$a[]="Amanda";
$a[]="Raquel";
$a[]="Cindy";
$a[]="Doris";
$a[]="Eve";
$a[]="Evita";
$a[]="Sunniva";
$a[]="Tove";
$a[]="Unni";
$a[]="Violet";
$a[]="Liza";
$a[]="Elizabeth";
$a[]="Ellen";
$a[]="Wenche";
$a[]="Vicky";
//從請求URL地址中獲取 q 參數(shù)
$q=$_GET["q"];
//查找是否由匹配值， 如果 q>0
if (strlen($q) > 0)
{
$hint="";
for($i=0; $i<count($a); $i++)
{
if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q))))
{
if ($hint=="")
{
$hint=$a[$i];
}
else
{
$hint=$hint." , ".$a[$i];
}
}
}
}
// 如果沒有匹配值設(shè)置輸出為 "no suggestion"
if ($hint == "")
{
$response="no suggestion";
}
else
{
$response=$hint;
}
//輸出返回值
echo $response;
?>Explanation: If JavaScript sends any text (i.e. strlen($q) > 0), this will happen:
Find names matching the characters sent by JavaScript
If no match is found, this will respond String set to "no suggestion"
If one or more matching names are found, set the response string with all names
Send the response to the "txtHint" placeholder
