Confining startDrag to x axis

I was looking at this tute:
http://www.kirupa.com/developer/flash5/follow.htm

How would I constrain it to the x axis?
Also, how can I put a maximum and minimum _x value on it, that it wil always stay between?
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I’m sure I know this already, just can’t remember…

[size=2]Edit: nevermind, looked in the flash help and you just need a couple more parameters.

Edit2: Ok, new question, I have this code, to make a little bar follow the mouse behind the menu, it works ok, but I can’t click the buttons anymore, and the rollOut doesn’t seem to work. Any ideas?

leftConstraint = 60
topConstraint = 0
rightConstraint = 420 
bottomConstraint = 0

this.onRollOver = function () {
	this.navBarBlocks.startDrag(true,leftConstraint,topConstraint,rightConstraint,bottomConstraint);
};

this.onRollOut = function () {
	this.navBarBlocks.stopDrag();
};

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