Ajax

Ajax(URL[, method[, data[, returnFunction]]])

Description

The Ajax function is used to get or receive data from a server. It is based on XMLHttpRequest. This function will only work when deployed to the website. It will not work when running in the local browser.

URL is the address on the server. It can be the name of a file to be downloaded from the server or a script to be run on the server. Optional information can be passed to the server at the end of the URL: for example http://www.nsbasic.com/getCustomerInfo.php?customer=Knuth will call the PHP script named getCustomerInfo.php, passing the parameter customer=Knuth.

Use method to define the access method. If this parameter is omitted, GET is used. The most common value for this is POST. POST responses are never cached, whereas GET responses can be. POST also allows larger data transfers. If you are using POST, put the information you want to send in data. The normal size limit for data is 8 megabytes: it is a server setting which can be increased. This is an easy and efficient way to send data to a server.

returnFunction, if supplied, is a function to be called when the results return, allowing asynchronous execution. If this parameter is not supplied, execution will continue at the next statement after the results return.

Other useful methods are DELETE and PUT. For more information on these options, see XMLHttpRequest's open method. For more information on other methods see HTTP request methods.

It returns two values: If .status = 0 or 200, the call was successful. Any data that is returned will be in .responseText. If the file is not read successfully, a status code is returned in .status.

See also samples Ajax and AjaxPost for more information.

Example

' AJAX example
req = Ajax("/sendData_ajax.php/?myText=" + txtSend.value) 
If req.status = 200 Then ' success
    txtResponse.value = req.responseText
Else ' failure
    txtResponse.value = "Error: " & req.err.message
End If

' Sample POST call
req = Ajax("/sendData_ajaxPost.php", "POST", txtSend.value)

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