PHP - AJAX 搜索

AJAX 是异步 JavaScript 和 XML 的简称。Ajax 用于构建快速且动态的网页。以下示例演示了与后端 PHP 脚本的交互，使用 AJAX 函数在网页上提供搜索字段。

步骤 1

将以下脚本保存为“example.php” -

<html>
<head>
   <style>
      span {
         color: green;
      }
   </style>
   <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", "hello.php?q=" + str, true);
            xmlhttp.send();
         }
      }
   </script>
</head>
<body>
   <p><b>Search your favourite tutorials:</b></p>
   <form>
      <input type = "text" onkeyup = "showHint(this.value)">
   </form>
   <p>Entered Course name: <span id="txtHint"></span></p>
</body>
</html>

此代码本质上是一个 HTML 脚本，它呈现一个带有文本字段的 HTML 表单。在其 **onkeyup** 事件中，调用 showHint() JavaScript 函数。该函数向服务器上的另一个 PHP 脚本发送 HTTP GET 请求。

步骤 2

将以下脚本保存为“php_ajax.php” -

<?php
   // Array with names
   $a[] = "Android";
   $a[] = "B programming language";
   $a[] = "C programming language";
   $a[] = "D programming language";
   $a[] = "euphoria";
   $a[] = "F#";
   $a[] = "GWT";
   $a[] = "HTML5";
   $a[] = "ibatis";
   $a[] = "Java";
   $a[] = "K programming language";
   $a[] = "Lisp";
   $a[] = "Microsoft technologies";
   $a[] = "Networking";
   $a[] = "Open Source";
   $a[] = "Prototype";
   $a[] = "QC";
   $a[] = "Restful web services";
   $a[] = "Scrum";
   $a[] = "Testing";
   $a[] = "UML";
   $a[] = "VB Script";
   $a[] = "Web Technologies";
   $a[] = "Xerox Technology";
   $a[] = "YQL";
   $a[] = "ZOPL";

   $q = $_REQUEST["q"];
   $hint = "";

   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";
            }
         }
      }
   }
   echo $hint === "" ? "Please enter a valid course name" : $hint;
?>

步骤 3

我们将通过在浏览器中打开 example.php 并输入 URL **https:///example.php** 来启动此应用程序。

在搜索字段中的每次击键时，都会向服务器发送一个 GET 请求。服务器脚本从 $_REQUEST 数组中读取字符并搜索匹配的课程名称。匹配的值显示在浏览器中文本字段下方。

打印页面