下面计算鼠标位置与canvas元素的关系:

const example = document.getElementById('example');

example.onmousemove = function(e) { 
    const x = e.pageX - e.currentTarget.offsetLeft; 
    const y = e.pageY - e.currentTarget.offsetTop; 
}

这是我得到的。

    $(".some-class").click(function(e) {

    var posx = 0;
    var posy = 0;

    posx = e.pageX;
    posy = e.pageY;

    alert(posx);
    alert(posy);
});

在我看来，上述答案都不令人满意，所以我用的是:

// Cross-browser AddEventListener
function ael(e, n, h){
    if( e.addEventListener ){
        e.addEventListener(n, h, true);
    }else{
        e.attachEvent('on'+n, h);
    }
}

var touch = 'ontouchstart' in document.documentElement; // true if touch device
var mx, my; // always has current mouse position IN WINDOW

if(touch){
    ael(document, 'touchmove', function(e){var ori=e;mx=ori.changedTouches[0].pageX;my=ori.changedTouches[0].pageY} );
}else{
    ael(document, 'mousemove', function(e){mx=e.clientX;my=e.clientY} );
}

// local mouse X,Y position in element
function showLocalPos(e){
    document.title = (mx - e.getBoundingClientRect().left)
        + 'x'
        + Math.round(my - e.getBoundingClientRect().top);
}

如果你需要知道页面当前的Y轴滚动位置:

var yscroll = window.pageYOffset
        || (document.documentElement && document.documentElement.scrollTop)
        || document.body.scrollTop; // scroll Y position in page

摘自本教程，感谢上面的评论做了更正:

function getMousePos( canvas, evt ) {
    var rect = canvas.getBoundingClientRect();
    return {
        x: Math.floor( ( evt.clientX - rect.left ) / ( rect.right - rect.left ) * canvas.width ),
        y: Math.floor( ( evt.clientY - rect.top ) / ( rect.bottom - rect.top ) * canvas.height )
    };
}

在画布上使用如下:

var canvas = document.getElementById( 'myCanvas' );
canvas.addEventListener( 'mousemove', function( evt ) {
    var mousePos = getMousePos( canvas, evt );
} );

通过事件可以获得画布内的鼠标坐标。offsetX和事件。下面是一个小片段来证明我的观点:

c=document.getElementById("c"); ctx=c.getContext("2d"); ctx.fillStyle="black"; ctx.fillRect(0,0,100,100); c.addEventListener("mousemove",function(mouseEvt){ // the mouse's coordinates on the canvas are just below x=mouseEvt.offsetX; y=mouseEvt.offsetY; // the following lines draw a red square around the mouse to prove it ctx.fillStyle="black"; ctx.fillRect(0,0,100,100); ctx.fillStyle="red"; ctx.fillRect(x-5,y-5,10,10); }); body { background-color: blue; } canvas { position: absolute; top: 50px; left: 100px; } <canvas id="c" width="100" height="100"></canvas>

下面计算鼠标位置与canvas元素的关系:

const example = document.getElementById('example');

example.onmousemove = function(e) { 
    const x = e.pageX - e.currentTarget.offsetLeft; 
    const y = e.pageY - e.currentTarget.offsetTop; 
}