javascript

function toDou(n){
return n < 10 ? '0' + n : '' + n;
}
window.onload = function() {
var oT = document.getElementById('t1');
var oBtn = document.getElementById('btn1');
var oBtn2 = document.getElementById('btn2');
var timer = null;
var num = parseInt(oT.value);
var bSin = false;
oBtn.onclick = function() {
if (bSin) {
return;
}
bSin = true;
clearInterval(timer);
function m(){
num++;
var iM = parseInt(num / 60);
var iS = num % 60;
oT.value = toDou(iM) + ':' + toDou(iS);
}
m();
timer = setInterval(m,1000);
};
oBtn2.onclick = function() {
clearInterval(timer);
bSin = false;
};
};

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在此查看效果：

function toDou(n) {
return n < 10 ? '0' + n : '' + n;
}
window.onload = function() {
var oDiv = document.getElementById('div1');
function clock(){
var oDate = new Date();
var iH = oDate.getHours();
var iM = oDate.getMinutes();
var iS = oDate.getSeconds();
oDiv.innerHTML = toDou(iH) + ':' + toDou(iM) + ':'+ toDou(iS);
}
clock();
setInterval(clock,1000);

运行代码

在此查看效果：
16:11:43

window.onload = function() {
var oBtn = document.getElementById('btn1');
var oBtn2 = document.getElementById('btn2');
var oBtn3 = document.getElementById('btn3');
var oDiv = document.getElementById('div2');
var aCk = oDiv.getElementsByTagName('input');
oBtn.onclick = function() {
for (var i = 0; i < aCk.length; i++) {
aCk[i].checked = true;
}
};
oBtn2.onclick = function() {
for (var i = 0; i < aCk.length; i++) {
aCk[i].checked = false;
}
};
oBtn3.onclick = function() {
for (var i = 0; i < aCk.length; i++) {
if (aCk[i].checked == true) {
aCk[i].checked = false;
}else {
aCk[i].checked = true;
}
}
};
};

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