ถามเรื่อง Class ใน Javascript มัน Error ตอนเอา Method มาใช้

/*Class Javascript ที่เขียนขึ้นมาครับ general.js*/
var General = function (){
	this.posX;
	this.posY;
};
General.prototype.addEventMouseMove=function(){
	if(window.addEventListener){
		window.addEventListener("mousemove",this.getPositionXY,true);
	}
	else if(window.attachEvent){
		d.onmousemove=this.getPositionXY;
	}
};
General.prototype.getPositionXY=function (e){
	var browser=new Browser();
	if(browser.browserName()=="FF" || browser.browserName()=="OPERA"){
		this.posX=e.pageX;
		this.posY=e.pageY;
	}
	else if(browser.browserName()=="IE"){
		this.posX=event.clientX + (document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft);
		this.posY=event.clientY + (document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop);
	}
};
General.prototype.setPosX=function (posX){this.posX=posX;};
General.prototype.getPosX=function (){return this.posX;};
General.prototype.setPosY=function (posY){this.posY=posY;};
General.prototype.getPosY=function (){return this.posY;};

/*main.php*/
<script type='text/javascript' src='general.js'></script>
<script type='text/javascript'>
	var g=new General();
	g.addEventMouseMove();
	var getPosXY=function(){
		alert(g.getPosX());
	}
</script>

<input type='button' id='button' value='Click Here' onClick='getPosXY()' />