javascript - html Canvas 中的关键灵敏度

Question

我需要知道在松开鼠标/按键之前按下了多长时间，因此响应将取决于按键/鼠标的按下。

例如，我试过这个，但出于某种原因它似乎不起作用。

var time = new Date();
var mousedown, mouseup, mousehold;

document.addEventListener('onmousedown', function(){
    mousedown = time.getTime(); //gets time when mouse was pressed
});

document.addEventListener('onmouseup', function(){
    mouseup = time.getTime(); //time when mouse was released
    mousehold = mouseup - mousedown; //time difference
    console.log(mousehold);
});

Answer 1

首先你应该使用

document.addEventListenter("mousedown", function() {...});

和

document.addEventListener("mouseup", function() {...}); '

其次，您的time.getTime 将获取time 变量的时间。 你应该这样做:

var mousedown, mouseup, mousehold;

document.addEventListener('mousedown', function(){
    mousedown = Date.now(); //gets time when mouse was pressed
});

document.addEventListener('mouseup', function(){
    mouseup = Date.now(); //time when mouse was released
    mousehold = mouseup - mousedown; //time difference
    console.log(mousehold);
});

这是一个更好的版本:

var mouseup, mousehold;

document.addEventListener('mousedown', function(){
    mousedown = Date.now(); //gets time when mouse was pressed
});

document.addEventListener('mouseup', function(){
    mousehold = Date.now()- mousedown; //time difference
    console.log(mousehold);
});

如果您只想计算 mousehold 变量，则无需使用 mouseup 变量。