AJAX是用来创造更多的交互式应用程序。
AJAX PHP实例
下面的例子将演示如何网页可以同时输入字段的用户类型字符的Web服务器通信：
例
Start typing a name in the input field below:
First name:Suggestions:
例子解释：
在上面的例子中，当用户在输入字段的字符，调用函数"showHint()"被执行。
该功能是由触发onkeyup事件。
下面是HTML代码：
例
<html>
<head>
<script>
function showHint(str) {
if (str.length == 0) {
document.getElementById("txtHint").innerHTML = "";
return;
} else {
var xmlhttp = new
XMLHttpRequest();
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>Start typing a name in the
input field below:</b></p>
<form>
First name: <input type="text"
onkeyup="showHint(this.value)">
</form>
<p>Suggestions: <span id="txtHint"></span></p>
</body>
</html> 试一试» 代码解释：
首先，检查输入字段为空(str.length == 0) 如果是，清除的内容txtHint占位符和退出的功能。
然而，如果输入字段不为空，执行以下步骤：
- 创建XMLHttpRequest对象
- 创建功能被执行时，服务器响应就绪
- 发送请求开了一个PHP文件(gethint.php)在服务器上
- 注意， q参数被添加gethint.php?q="+str
- 该str变量保存输入字段的内容
PHP文件- "gethint.php"
PHP文件检查名称的数组，并返回相应的name(s)到浏览器：
<?php
// Array with names
$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";
// get the q parameter from URL
$q = $_REQUEST["q"];
$hint = "";
//
lookup all hints from array if $q is different from ""
if ($q !== "")
{
$q = strtolower($q);
$len=strlen($q);
foreach($a as
$name) {
if (stristr($q, substr($name, 0, $len)))
{
if ($hint === "") {
$hint = $name;
} else
{
$hint .= ", $name";
}
}
}
}
// Output "no suggestion" if no hint was found
or output correct values
echo $hint === "" ? "no suggestion" : $hint;
?>