AJAX Live Search

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:

Example:

<html>

<head>

<script type="text/javascript">

function showResult(str)

{

if (str.length==0)

  {

  document.getElementById("livesearch").innerHTML="";

  document.getElementById("livesearch").style.border="0px";

  return;

  }

if (window.XMLHttpRequest)

  {// code for IE7+, Firefox, Chrome, Opera, Safari

  xmlhttp=new XMLHttpRequest();

  }

else

  {// code for IE6, IE5

  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 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)

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:

Example:

<?php

$xmlDoc=new DOMDocument();

$xmlDoc->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="<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>";

        }

      }

    }

  }

}



// 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 <title> elements to find matches from the text sent from the JavaScript
    * Sets 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, the $response variable is set to "no suggestion"

AJAX Live Search

Example Explained The HTML Page

The PHP File

Web Tutorials