question about events..

[RussellReal]

ok I have an object right

 

lets say sumfin like this:

 

function handleThisEvent() {
  // HOW do I reference this event's CALLING xmlHTTPRequest object?
}
function What() {
  a = new XMLHttpRequest();
  a.open("GET","whatever.php",true);
  a.send(null);
  a.onreadystatechange = handleThisEvent;
}
abc = new What();

inside handleThisEvent how would I reference "a" the xmlHTTPRequest object specified in the What object..

 

without making a global variable equal to "a"

[KevinM1]

ok I have an object right

 

lets say sumfin like this:

 

function handleThisEvent() {
  // HOW do I reference this event's CALLING xmlHTTPRequest object?
}
function What() {
  a = new XMLHttpRequest();
  a.open("GET","whatever.php",true);
  a.send(null);
  a.onreadystatechange = handleThisEvent;
}
abc = new What();

inside handleThisEvent how would I reference "a" the xmlHTTPRequest object specified in the What object..

 

without making a global variable equal to "a"

 

Hmm...have you tried using 'this', or 'this.a'?

[emehrkay]

You'll have to "bind" the "this" state of the a object to the xmlHTTPRequest object.

 

You can do that with the pass function. It is kinda difficult to understand, but I found a great example at mozilla's dev site. Let me see if I can find it.

[emehrkay]

sorry, pass is a MooTool specific function. What I was talking about was the apply method

 

https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Function/apply

 

Check out this example in firebug

function a(){

this.property = 'a property';

}

 

b = function(){

console.log(this.property);

}

 

x = new a();

 

y = b.apply(x);  //b's "this" is now the same as x. If b had arguments, you'd pass it as an array as the second argument of apply