AJAX Introduction by Bhanwar Gupta - HTML preview

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XMLHttpRequest Properties

• onreadystatechange

– Event handler that fires at each state change

– You implement your own function that handles this

• readyState – current status of request

– 0 = uninitialized
– 1 = loading
– 2 = loaded
– 3 = interactive (some data has been returned)

• This is broken in IE right now

– 4 = complete

• status

– HTTP Status returned from server: 200 = OK

• responseText

– String version of data returned from server

• responseXML

– XML DOM document of data returned

• statusText

– Status text returned from server

• // get an XMLHTTPRequest object
• // build a url variable, call it url
• // open a connection with the server

• /* prepare to receive response, i.e. give it to a function */
• // send the request

• var myRequest = getXMLHTTPRequest( ); • function callAjax( ) // javascript code • { • var url = “test.php?mike”; • myRequest.open( “GET”, url, true ); • myRequest.onreadystatechange = responseAjax(); • myRequest.send( null ); • }