PHP Example - AJAX Live Search

AJAX can be used to create more user-friendly and interactive searches.

AJAX Live Search

The following example will demonstrate a live search, where you get search results while you type.

Live search has many benefits compared to traditional searching:

• Results are shown as you type
• Results narrow as you continue typing
• If results become too narrow, remove characters to see a broader result

Example Explained - The HTML Page

When a user types a character in the input field above, the function "showResult()" is executed. The function is triggered by the "onkeyup" event:

Source code explanation:

If the input field is empty (str.length==0), the function clears the content of the livesearch placeholder and exits the function.

If the input field is not empty, the showResult() function executes the following:

• Create an XMLHttpRequest object
• Create the function to be executed when the server response is ready
• Send the request off to a file on the server
• Notice that a parameter (q) is added to the URL (with the content of the input field)

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The PHP File

The page on the server called by the JavaScript above is a PHP file called "livesearch.php".

The source code in "livesearch.php" searches an XML file for titles matching the search string and returns the result:

load("links.xml"); $x=$xmlDoc->getElementsByTagName('link'); //get the q parameter from URL $q=$_GET["q"]; //lookup all links from the xml file if length of q>0 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) { //find a link matching the search text if (stristr($y->item(0)->childNodes->item(0)->nodeValue,$q)) { if ($hint=="") { $hint="" . $y->item(0)->childNodes->item(0)->nodeValue . ""; } else { $hint=$hint . " " . $y->item(0)->childNodes->item(0)->nodeValue . ""; } } } } } // Set output to "no suggestion" if no hint were found // or to the correct values if ($hint=="") { $response="no suggestion"; } else { $response=$hint; } //output the response echo $response; ?>

If there is any text sent from the JavaScript (strlen($q) > 0), the following happens:

• Load an XML file into a new XML DOM object
• Loop through all