The following standard code is used to create the XMLHttpRequest object. This code works with Internet Explorer (the first part) and Firefox browser (the second part). The XMLHttpRequest object has to be created in order to use the AJAX technology (AJAX = Asynchronous JavaScript And Xml).
function createXMLHttpRequest()
{
if (window.ActiveXObject)
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
else if (window.XMLHttpRequest)
xmlHttp = new XMLHttpRequest();
}
|
Once the XMLHttpRequest object is created, you can use its methods and properties shown in the following tables:
| XMLHttpRequest Methods | Description |
|---|---|
| abort() | abort current request |
| getAllResponseHeaders() | returns all the response headers as the key/value pairs |
| getResponseHeader("header") | returns the value of a specific header (as a string) |
| open("method", "url") | sets up a call to the url script by using GET or POST method |
| send(content) | sends the request to the server |
| setRequestHeader("header", "value") | sets up a specific header after calling the open() method |
The method open() also takes three optional tailing arguments:
The async instructs the browser to make synchronous or asynchronous (default value) requests. The last two parameters allow to include user's name and password.
| XMLHttpRequest Properties | Description |
|---|---|
| onreadystatechange | event handler that usually launches a JavaScript function |
| readyState | 0 = uninitialized 1 = loading 2 = loaded 3 = interactive 4 = complete |
| responseText | response from a server as a string |
| responseXML | response from a server as an XML object |
| status | status code from server: 200 = OK, 404 = not found, etc |
| statusText | text version of the status code |