[javascript] 마우스 위치 알아내기

var tempX = 0;
var tempY = 0;
tempX = event.clientX + 　document.body.scrollLeft;
tempY = event.clientY + 　document.body.scrollTop;
if (tempX < 0){tempX = 0;}
if (tempY < 0){tempY = 0;}

var skn1 = Form.style;
skn1.left = tempX - 250;
skn1.top = tempY + 20;

skn1.visibility="visible"