此代码适用于 Google Chrome 和 IE,但不适用于 FireFox。
function drawChildren(names) {
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
var ctxcolor = "#000000";
if(listeners < 1){
c.addEventListener("click", getPosition, false);
listeners = 1;
} // At the click function "getPosition" is executed
}
function getPosition(event) {
if ( event.offsetX == null ) { // Firefox
clickedX = event.layerX;
clickedY = event.layerY;
} else { // Other browsers
clickedX = event.offsetX;
clickedY = event.offsetY;
}
checkCoordinates(clickedX, clickedY);
}