确定屏幕上哪个对象点击了html5 canvas javascript？

// 'e' is the DOM event object
// 'c' is the canvas element
// 'units' is the array of unit objects
// (assuming each unit has x/y/width/height props)

var y = e.pageY,x = e.pageX,cOffset = $(C).offset(),clickedUnit;

// Adjust x/y values so we get click position relative to canvas element
x = x - cOffset.top;
y = y - cOffset.left;
// Note,if the canvas element has borders/outlines/margins then you
// will need to take these into account too.

for (var i = -1,l = units.length,unit; ++i < l;) {
    unit = units[i];
    if (
        y > unit.y && y < unit.y + unit.height &&
        x > unit.x && x < unit.x + unit.width
    ) {
        // Escape upon finding first matching unit
        clickedUnit = unit;
        break;
    }
}

// Do something with `clickedUnit`

注意,这不会处理复杂的交叉对象或z-index问题等……只是一个真正的起点.