触发鼠标事件时，clientY鼠标事件属性用于获取鼠标指针的垂直坐标。这是根据当前窗口。
您可以尝试运行以下代码，以了解如何在JavaScript中实现clientY Mouse事件。
<!DOCTYPE html>
<html>
<body>
<p onclick = "coordsFunc(event)">Click here to get the x (horizontal) and y (vertical) coordinates (according to current window) of the mouse pointer.</p>
<script>
function coordsFunc(event) {
var x_coord = event.clientX;
var y_coord = event.clientY;
var xycoords = "X coords= " + x_coord + ", Y coords = " + y_coord;
document.write(xycoords);
}
</script>
</body>
</html>