Where when why – Nothing

Okay so I have been messing around with all this ajax stuff recently. Now being a big fan of SMARTY I was reluctant to go and write my own templating system, and intergrating javascript into some of the existing smarty templates I had was a bit of a pain in the ass. But I really wanted to give this AJAX stuff a go.

After trying various different ajax scripts and implementatons, I settled on XAjax to work with PHP. The main reason was that they seemed to be the easiest to intergrate with Smarty.

So down to the nuts and bolts of it.

require_once(INCLUDESDIR. '/3rdparty/Xajax/xajax.inc.php');
$xajax = new xajax();
// Send our xajax requests to a certain server
$xajax->setRequestURI("form-processor.php");
$xajax->registerFunction("validate-field");
$xajax->processRequests();
$smarty->assign('xajax_javascript', $xajax->getJavascript());
$smarty->display('web/common/header.tpl');


So lets go this bit by bit just so that we are clear.

The first line simply includes or Xajax script

Begin a new instance of Xajax

The next line tells Xajax where to send the data. By default it will use POST and send the data back to the same calling script. However in this example, I am sending the data to another script whihc does all the processing for me and returns the results as an Xajax response.

Finally the register functions tells Xajax which function to call based upon what you write and decide it is allowed to call.

The process request statement must be called otherwise you won’t get anything back from your scripts

Xajax makes it very easy for you, all you do is as normal is assign a smarty var, the Xajax javascript and call it in your template as you would normally call anything else.

No an important bit here. If like me you are sending your requests to a separate script, you must include the Xajax library, you must have xajax registered the functions and you must call xajax->processRequests();

A function, for those that don’t know can be anything you want to do. The validate one looks like this;


public function validate-field($arg1) {
$objResponse = new xajaxResponse();
if(!$arg1, !$arg2) {
return false;
}
$objResponse->addClear("messages","innerHTML");
$objResponse->addAssign('messages', 'innerHTML', "Form was validated");
return $objResponse->getXML();
}


You must return the $objResponse->getXML(), otherwise, how is XAJAX supposed to know what to do?

So on my form, I have a on blur event that simply valiades the filed after the user moves away from the field

This simple gets the value of the field and passes it to xajax whihc then calls my function. Simple right.

Now I have actually got it to send messages like processing data, and then display an error message, perhaps I will put up an example of those when I get a chance.

BTW this is a very very simplifed example of how quick it is to add XAJAX into your scripts. However please note that it can be quite complex to do this, and you should sit and plan your application correctly and its data flow. Also remember don’t use AJAX just because its cool to do so, use it because there is actually a need to use it.

This entry was posted on Saturday, December 31st, 2005 at 8:07 pm and is filed under PHP. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.