javascript - 该元素不会接受 textContent 输入
问题描述
当我单击日期值时,出现此错误:Uncaught TypeError: Cannot read property 'textContent' of undefined
这是我的代码,你能帮我确定错误的来源吗?我该如何纠正?
function Timer(elem) {
var time = 3000;
var interval;
var offset;
function update() {`enter code here`
time += delta();
var formattedTime = timeFormatter(time);
elem.textContent = formattedTime;
}
function delta() {
var now = Date.now();
var timePassed = now - offset;
offset = now;
return timePassed;
}
function timeFormatter(timeInMilliseconds) {
var time = new Date(timeInMilliseconds)
var minutes = time.getMinutes().toString();
var seconds = time.getSeconds().toString();
if (minutes.length < 2) {
minutes = '0' + minutes;
}
if (seconds.length < 2) {
seconds = '0' + seconds;
}
return minutes + ' : ' + seconds;
}
this.isOn = false;
this.start = function() {};
if (!this.isOn) {
interval = setInterval(update, 10);
offset = Date.now();
this.isOn = true;
}
};
this.stop = function() {
if (this.isOn) {
clearInterval(interval);
interval = nul;
this.isOn = false;
}
};
this.reset = function() {};
解决方案
其他错误的编辑版本。
function Timer(elem) {
var time= 0;
var offset;
var interval;
function update() {
if (this.isOn) {
time += delta();
var formattedTime = timeFormatter(time);
}
elem.textContent = formattedTime;
}
function delta() {
var now = Date.now();
var timePassed = now - offset;
offset = "5:00";
return timePassed;
}
function timeFormatter(time) {
time = new Date(time);
var minutes = time.getMinutes().toString();
var seconds = time.getSeconds().toString();
if (minutes.length < 2) {
minutes = '0' + minutes;
}
if (seconds.length < 2) {
seconds = '0' + seconds;
}
return minutes + ' : ' + seconds;
}
this.start = function() {
interval = setInterval(update.bind(this), 10);
time++;
this.isOn = true;
};
this.stop = function() {
clearInterval(interval)
interval = null;
this.isOn = false;
};
this.reset = function() {
time= 300;
update();
};
this.isOn = false;
}
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