[Javascript] Prevent Prototype Ajax from firing twice

[Scott Reynen]

On Feb 20, 2008, at 3:45 AM, Michael Borchers wrote:

> Is there a way to prevent Prototype doing one AJAX call several  
> times? F.e. writing it into a var or getting a global AJAX status  
> and to check if it already exists?


I just recently did this in JQuery and was surprised it wasn't already  
built in (that I could find, anyway).  What I did was just create a  
global urlRequested array, and then make requests something like this:

if ( ! urlRequested[ url ] )
{

	urlRequested[ url ] = true;
	// request url

}

If you're only seeking to prevent duplicate requests while the first  
request is pending, you can set urlRequested[ url ] = false in your  
response handler.  Otherwise the requests will only go once ever.   
This gets more complicated if your requests are distinguished by more  
than just URL, but the same general technique should work.

Peace,
Scott