event.clientX的问题

Question

function cnvs_getCoordinates(e)

{

x=e.clientX;

y=e.clientY;

document.getElementById("xycoordinates").innerHTML="Coordinates: (" + x + "," + y + ")";

}

为什么非要传个参数,有什么好处,下面这么些有什么不同?

function cnvs_getCoordinates()

{

x=event.clientX;

y=event.clientY;

document.getElementById("xycoordinates").innerHTML="Coordinates: (" + x + "," + y + ")";

}

Answer 1

传参是为了兼容,因为有的浏览器不兼容 event 属性这是就会在函数的内部开头增加一行代码 var ev = e || window.event;