JavaScript中Date对象的常用方法示例

getFullYear()
使用 getFullYear() 获取年份。
源代码:

</script>
<!DOCTYPE html>
<html>
<body>
​
<p id="demo">Click the button to display the full year of todays date.</p>
​
<button onclick="myFunction()">Try it</button>
​
<script>
function myFunction()
{
var d = new Date();
var x = document.getElementById("demo");
x.innerHTML=d.getFullYear();
}
</script>
​
</body>
</html>

测试结果:

2015

getTime()
getTime() 返回从 1970 年 1 月 1 日至今的毫秒数。
源代码:

<!DOCTYPE html>
<html>
<body>
​
<p id="demo">Click the button to display the number of milliseconds since midnight, January 1, 1970.</p>
​
<button onclick="myFunction()">Try it</button>
​
<script>
function myFunction()
{
var d = new Date();
var x = document.getElementById("demo");
x.innerHTML=d.getTime();
}
</script>
​
</body>
</html>

测试结果:

1445669203860

setFullYear()
如何使用 setFullYear() 设置具体的日期。
源代码:

<!DOCTYPE html>
<html>
<body>
​
<p id="demo">Click the button to display a date after changing the year, month, and day.</p>
​
<button onclick="myFunction()">Try it</button>
​
<script>
function myFunction()
{
var d = new Date();
d.setFullYear(2020,10,3);
var x = document.getElementById("demo");
x.innerHTML=d;
}
</script>
​
<p>Remember that JavaScript counts months from 0 to 11.
Month 10 is November.</p>
</body>
</html>

测试结果:

Tue Nov 03 2020 14:47:46 GMT+0800 (中国标准时间)

toUTCString()
如何使用 toUTCString() 将当日的日期（根据 UTC）转换为字符串。

源代码:

<!DOCTYPE html>
<html>
<body>
​
<p id="demo">Click the button to display the UTC date and time as a string.</p>
​
<button onclick="myFunction()">Try it</button>
​
<script>
function myFunction()
{
var d = new Date();
var x = document.getElementById("demo");
x.innerHTML=d.toUTCString();
}
</script>
​
</body>
</html>

测试结果:

Sat, 24 Oct 2015 06:49:05 GMT

getDay()
如何使用 getDay() 和数组来显示星期，而不仅仅是数字。
源代码:

<!DOCTYPE html>
<html>
<body>
​
<p id="demo">Click the button to display todays day of the week.</p>
​
<button onclick="myFunction()">Try it</button>
​
<script>
function myFunction()
{
var d = new Date();
var weekday=new Array(7);
weekday[0]="Sunday";
weekday[1]="Monday";
weekday[2]="Tuesday";
weekday[3]="Wednesday";
weekday[4]="Thursday";
weekday[5]="Friday";
weekday[6]="Saturday";
​
var x = document.getElementById("demo");
x.innerHTML=weekday[d.getDay()];
}
</script>
​
</body>
</html>  

测试结果:

Saturday

Display a clock
如何在网页上显示一个钟表。
源代码:

<!DOCTYPE html>
<html>
<head>
<script>
function startTime()
{
var today=new Date();
var h=today.getHours();
var m=today.getMinutes();
var s=today.getSeconds();
// add a zero in front of numbers<10
m=checkTime(m);
s=checkTime(s);
document.getElementById('txt').innerHTML=h+":"+m+":"+s;
t=setTimeout(function(){startTime()},500);
}
​
function checkTime(i)
{
if (i<10)
 {
 i="0" + i;
 }
return i;
}
</script>
</head>
​
<body onload="startTime()">
<div id="txt"></div>
</body>
</html>