e.changedTouches[0].pageX - uncaught TypeError: Cannot read property '0' of undefined

问题

Well, i need to get the touch position in hand devices. For that i have use below code

var touchX = e.changedTouches[0].pageX;

on tap I'm getting the position of it as expected. But in the console there is a error thrown as below:

Uncaught TypeError: Cannot read property '0' of undefined at HTMLDocument.mouseover (index1.html:152)

Can someone help me on this.

回答1:

found the answer. We need to use device specific conditions for touch events and mouse event.

var docWidth = window.innerWidth;
if(docWidth <= 1024){
                var touchX = e.changedTouches[0].pageX;
                var touchY = e.changedTouches[0].pageY;
                mouseout(e)
            }
            else{
                var mouseX = e.clientX;
                var mouseY = e.clientY;
            }

来源：https://stackoverflow.com/questions/49230576/e-changedtouches0-pagex-uncaught-typeerror-cannot-read-property-0-of-unde