Xajax and PHP: JavaScript without the pain

Automatic for the people

Also specify in the tags of the input form that Xajax should generate any required JavaScript after an XML response has been sent back from the server.

<?php $xajax->printJavascript('./xajax');
?>

A XMLHttpRequest is initiated by a client application. In the example application, a XMLHttpRequest is initiated by the onkeyup event handler in input field catalogId.

<tr><td>Catalog Id:</td><td><input    type="text"
            size="20"  
              id="catalogId"
            name="catalogId"
    autocomplete="off"
         onkeyup="xajax_validateCatalogId(xajax.getFormValues('validationForm'));"></td>
         <td><div id="validationMessage"></div></td>
</tr>

The input field invokes the wrapper function xajax_validateCatalog with an array of form field values as a parameter. The wrapper functions send a XMLHttpReques to the server. The xajaxobject receives the XMLHttpRequest and invokes the corresponding PHP function validateCatalogId($formValues).

Process an Ajax request

Xajax provides the xajaxResponseclass to send a response to the client application. In the validateCatalogId function, create a xajaxResponse object.

$objResponse = new xajaxResponse();

The validateCatalogId function validates a Catalog Id value added in the input form. From the $formValues array retrieve the value of the catalogId field.

$catalogId=trim($formValues['catalogId']); 

Next, use the PHP Oracle extension to connect with the Oracle database and determine if a Catalog table row is defined for the catalog id value input in the input form. If the result set is empty, a Catalog table row for the catalog id value is not defined in the database table. Therefore, the Catalog Id field value added in the form is valid.

Next, we shall generate a response to be sent to the client application. A response contains one or more command messages. Some of the commonly used command messages are discussed in table below.

Command Message	Description
Assign	Sets the specified attribute of an element in input page with method addAssign().
Append	Appends data to the specified attribute of an element in the input page with method addAppend().
Prepend	Prepends data to the specified attribute of an element in the input page with method addPrepend().
Replace	Replaces data in the specified attribute of an element in the input page with method addReplace().
Script	Runs the specified JavaScript code with method addScript().
Alert	Displays an alert box with the specified message with method addAlert().