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
The results in the example above are found in an XML file (links.xml). To make this example small and simple, only eight results are available.
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:| <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> |
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:
| <?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 $response; ?> |
- Load an XML file into a new XML DOM object
- Loop through all <title> elements to find matches from the text sent from the JavaScript
- Sets the correct url and title in the "$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"
No comments:
Post a Comment