# \[FMX\] need better explanation

**URL:** <https://forum.kirupa.com/t/fmx-need-better-explanation/110801>\
**Category:** Uncategorized\
**Created:** [May 19, 2004, 9:41pm UTC](https://forum.kirupa.com/t/fmx-need-better-explanation/110801 "2004-05-19T21:41:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![DChihorn](https://avatars.discourse-cdn.com/v4/letter/d/eb8c5e/32.png) [@DChihorn](https://forum.kirupa.com/u/DChihorn)\
**Post date:** [May 19, 2004, 9:41pm UTC](https://forum.kirupa.com/t/fmx-need-better-explanation/110801/1 "2004-05-19T21:41:40Z")

</div>

About a month ago, someone posted this FLA. It is just a simple thing to give example of animated button (where the animation still happens even if you roll your mouse out early). It works, this is not a problem of the code.

They even went so far as to write some descriptions of what was happening along the way. I am able to follow along 95% of the way, but not 100%. And, I do want to actually learn this and not just copy paste it into other applications. So, I am hoping that someone can take just a minute and dive in a little deeper with the explanations to help me better understand it.

Specifically:

Line 13: 2 questions - what does “this” refer to? and which frame is it referrign to related to the onEnterFrame?

Lines 18-19: Still not really sure what this does or why? I think its meant to stop the action, but isnt that what the stop() inside the related MC does?

I have attached the FLA just in case you need it to follow along better. But, here is the main timeline actions:

```auto

// browse through everything in the movieclip
for (all in this) {
	/* only use the instances of a button of which 
	   the name begins with "btn",
	   so basically only use our menu buttons */
	if (this[all] instanceof Button && this[all]._name.substr(0, 3) == "btn") {
		/* set onRollOver handler for the buttons to make the 
		   animation move forward when rolled over */
		this[all].onRollOver = function() {
			/* set the onEnterFrame handler for the movieclip 
			   mc+ the number of the current button,
			   so for btn1 mc1 and for btn2 mc2 ... */
			this._parent["mc"+this._name.substr(3, 1)].onEnterFrame = function() {
				// make it go to the next frame
				this.nextFrame();
				/* if the current frame is the last frame, 
				   delete the onEnterFrame handler */
				if (this._currentframe == 16) {
					delete this.onEnterFrame;
				}
			};
		};
		/* set onRollOut handler for the buttons to make the 
		   animation move backwards when rolled out */
		this[all].onRollOut = function() {
			this._parent["mc"+this._name.substr(3, 1)].onEnterFrame = function() {
				this.nextFrame();
				if (this._currentframe == 2) {
					delete this.onEnterFrame;
				}
			};
		};
	}
}

```

Thanks for your time.