Js errors occur occasionally here

[502zl]

if (o.ignoreInputTextSelection) {
var clientX = getCoord('clientX', e);
var clientY = getCoord('clientY', e);
var elementBehindCursor = doc.elementFromPoint(clientX, clientY);
if (isInput(elementBehindCursor)) {
return;
}
}

Tips：elementBehindCursor maybe a null.