PHP Example - AJAX Real-Time Search
AJAX provides users with a more friendly and interactive search experience.
AJAX Live Search
In the following example, we will demonstrate a real-time search that provides results as you type.
Real-time search has many advantages over traditional search:
- Displays matching results as you type data
- Filters results as you continue to type
- If the results are too narrow, deleting characters expands the range
Enter "HTML" in the text box below to search for pages containing HTML:
The results in the above example are found in an XML file (links.xml). To keep this example small and simple, we only provide 6 results.
Example Explanation - HTML Page
When a user types characters in the input box above, the "showResult()" function is executed. This function is triggered by the "onkeyup" event:
<html>
<head>
<script>
function showResult(str)
{
if (str.length==0)
{
document.getElementById("livesearch").innerHTML="";
document.getElementById("livesearch").style.border="0px";
return;
}
if (window.XMLHttpRequest)
{// IE7+, Firefox, Chrome, Opera, Safari browsers execute
xmlhttp=new XMLHttpRequest();
}
else
{// IE6, IE5 browsers execute
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("livesearch").innerHTML=xmlhttp.responseText;
document.getElementById("livesearch").style.border="1px solid #A5ACB2";
}
}
xmlhttp.open("GET","livesearch.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<form>
<input type="text" size="30" onkeyup="showResult(this.value)">
<div id="livesearch"></div>
</form>
</body>
</html>
Source Code Explanation:
If the input box is empty (str.length==0), the function clears the content of the livesearch placeholder and exits.
If the input box is not empty, showResult() performs the following steps:
- Creates an XMLHttpRequest object
- Creates a function that executes when the server response is ready
- Sends a request to a file on the server
- Note the parameter (q) added to the URL (containing the content of the input box)
PHP File
The server page called by the JavaScript above is a PHP file named "livesearch.php".
The source code in "livesearch.php" searches the XML file for titles matching the search string and returns the results:
<?php
$xmlDoc=new DOMDocument();
$xmlDoc->load("links.xml");
$x=$xmlDoc->getElementsByTagName('link');
// Get the value of parameter q from the URL
$q=$_GET["q"];
// If q parameter exists, search data in the XML file
if (strlen($q)>0)
{
$hint="";
for($i=0; $i<($x->length); $i++)
{
$y=$x->item($i)->getElementsByTagName('title');
$z=$x->item($i)->getElementsByTagName('url');
if ($y->item(0)->nodeType == 1) {
// Found a link matching the search
if (stristr($y->item(0)->childNodes->item(0)->nodeValue, $q)) {
if ($hint == "") {
$hint = "<a href='" .
$z->item(0)->childNodes->item(0)->nodeValue .
"' target='_blank'>" .
$y->item(0)->childNodes->item(0)->nodeValue . "</a>";
} else {
$hint = $hint . "<br /><a href='" .
$z->item(0)->childNodes->item(0)->nodeValue .
"' target='_blank'>" .
$y->item(0)->childNodes->item(0)->nodeValue . "</a>";
}
}
}
// If no matches are found, return "no suggestion"
if ($hint == "") {
$response = "no suggestion";
} else {
$response = $hint;
}
// Output the result
echo $response;
?>
If JavaScript sends any text (i.e., strlen($q) > 0), the following occurs:
Load the XML file into a new XML DOM object
Traverse all <title> elements to find matches with the text sent by JavaScript
Set the correct URL and title in the "$response" variable. If more than one match is found, all matches are added to the variable.
If no matches are found, set the $response variable to "no suggestion".