ActionScript for Flash MX: The Definitive Guide, Second Edition

LoadVars.loaded Property

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ActionScript Language Reference

Usage

In practice, the load( ) and sendAndLoad( ) methods may not trigger a download if the vari-

ables at

url are cached by the browser hosting the Flash movie. To force the browser to

always download variables (and bypass its cache) we can use a query string with a dummy

variable that contains a unique value. By convention, the current time in milliseconds is

used, as it is assumed to be sufficiently unique. For example:

theVars = new LoadVars();

theVars.load("http://www.site.com/vars.txt?cacheKiller=" + new Date().getTime());

The same effect can be achieved using the sendAndLoad( ) method to invoke an HTTP GET

request with a dummy variable (

cacheKiller):

varSender = new LoadVars();

varReceiver = new LoadVars();

varSender.cacheKiller = new Date().getTime();

varSender.sendAndLoad("http://www.yourserver.com/vars.txt", varReceiver, "GET");

In all cases, data should be verified inside the onLoad( ) handler before being used, because

cached data can be corrupt or incomplete. See LoadVars.onLoad( ) for an example.

Example

The following code uses a LoadVars object to retrieve the variable in the text file vars.txt,

which looks like this:

msg1=hello+world

Two variations of load( ) are shown, one with a unique cache-prevention variable: ...