我正在练习javascript,并创建了一个带有两个骰子和数字1-12的小骰子掷东西。掷骰子,与掷骰子总数匹配的数字 (1-12( 得到一个红色虚线边框,当您单击它时,它会变成灰色。
我的图像源是"die_1"到"die_6",我只是随机生成一个数字 1-6,然后将其放入"die_"字符串中以更改图像的 src。
现在,如果您滚动的数字已经是灰色的,我会弹出一个警报,上面写着"再次滚动"。
我的问题是:在我当前的实现中,警报会在骰子图像更改之前弹出。一旦我单击"确定",骰子就会改变以显示掷出的数字。有没有办法延迟警报,直到骰子的图像发生变化?
var diePicture1 = document.getElementById("die1");
var diePicture2 = document.getElementById("die2");
const NUMBERBUTTONS = document.querySelectorAll(".number-button");
buttonRoll = document.getElementById('roll');
/* Gets the values of the dice and adds them */
function totalDice(){
var die1Value = parseInt(diePicture1.src.substring(diePicture1.src.length - 5,diePicture1.src.length-4));
var die2Value = parseInt(diePicture2.src.substring(diePicture2.src.length - 5,diePicture1.src.length-4));
var result = die1Value + die2Value;
return result;
}
buttonRoll.addEventListener('click', function(){
/*Randomly generates two numbers 1-6
then changes the img src to match */
var dieNumber1 = Math.floor(Math.random()*6) +1;
var dieNumber2 = Math.floor(Math.random()*6) +1;
diePicture1.src = "die_" + dieNumber1 +".png";
diePicture2.src = "die_" + dieNumber2 +".png";
var total = totalDice();
/*Checks to see if there are any numbers leftover
with a red border. If so, clears them */
currentNumber = NUMBERBUTTONS[total-1];
for (i=0; i<12; i++) {
if (NUMBERBUTTONS[i].style.border = "2px dashed red"){
NUMBERBUTTONS[i].style.border = "";
}
}
/*Gives red border if the color is not gray already */
if (currentNumber.style.background != "gray") {
currentNumber.style.border = "2px dashed red";
} else {
/*this is what is popping up before the dice images have had a chance
to change on screen */
alert("Roll Again");
}
}, false);
/*Turns number gray when clicked on IF border is red */
document.addEventListener('click',function(e){
if (e.target.style.border === "2px dashed red"){
e.target.style.border = "";
e.target.style.background = "gray";
}
},false);
很简单。set 超时函数需要两个参数,即要运行的内容以及要运行的时间,因此请将警报放入方法中并设置超时。
点击链接了解更多详情https://www.w3schools.com/js/js_timing.asp
您是否尝试过添加 setTimeOut 方法?将弹出警报的超时设置为在骰子的图像更改之后。
尝试使用承诺。
var dieNumber1 = Math.floor(Math.random()*6) +1;
var dieNumber2 = Math.floor(Math.random()*6) +1;
diePicture1.src = "die_" + dieNumber1 +".png";
diePicture2.src = "die_" + dieNumber2 +".png";
var total = totalDice();
var promise1 = new Promise((resolve, reject) => {
diePicture1.addEventListener('load', () => {
resolve();
})
})
var promise2 = new Promise((resolve, reject) => {
diePicture2.addEventListener('load', () => {
resolve();
})
})
...
Promise.all([promise1, promise2]).then(() => {alert('Roll Again')})
在这里,在加载两个图像之前,警报不会发生。