Tạo đồng hồ bằng javascript

Dưới đây là đoạn code chương trình hiển thị đồng hồ bằng javascript, Bạn có thể thay đổi màu của đồng hồ

1. Chèn đoạn code sau vào tệp tài liệu HTML
Code:

<script type="text/javascript">
function showtime(){
if (!document.all& &!document.getElementById)
return
thelement=document.getElementById? document.getElementById("tick2"): document.all.tick2
var Digital=new Date()
var hours=Digital.getHours()
var minutes=Digital.getMinutes()
var seconds=Digital.getSeconds()
var dn="PM"
if (hours<12)
dn="AM"
if (hours>12)
hours=hours-12
if (hours==0)
hours=12
if (minutes<=9)
minutes="0"+minutes
if (seconds<=9)
seconds="0"+seconds
var ctime=hours+":"+minutes+":"+seconds+" "+dn
thelement.innerHTML="<b style='font-size:14;color:blue;'>"+ctime+"</b>"
setTimeout("showtime()",1000)
}
window.onload=showtime
</script>

2. Chèn vào trong thẻ này <span id=tick2></span>

3. Để thay đồi màu của đồng hồ
thelement.innerHTML="<b style='font-size:14;color:blue;'>"+ctime+"</b>"

Bạn có thể đổi màu "color:blue;" (xanh) thành "color:red;" (đỏ) hoặc "color:black;" (đen)…..

Code 2:

<script language="JavaScript">

//Analog clock script- By VnTim™ (admin@vntim.co.cc)
//Script featured on Dynamic Drive
//Visit http://vntim.blogspot.com/ for this script and more

fCol='444444'; //face colour.
sCol='FF0000'; //seconds colour.
mCol='444444'; //minutes colour.
hCol='444444'; //hours colour.

Ybase=30; //Clock height.
Xbase=30; //Clock width.

H='...';
H=H.split('');
M='....';
M=M.split('');
S='.....';
S=S.split('');
NS4=(document.layers);
NS6=(document.getElementById&&!document.all);
IE4=(document.all);
Ypos=0;
Xpos=0;
dots=12;
Split=360/dots;
if (NS6){
for (i=1; i < dots+1; i++){
document.write('<div id="n6Digits'+i+'" style="position:absolute;top:0px;left:0px;width:30px;height:30px;font-family:Arial;font-size:10px;color:#'+fCol+';text-align:center;padding-top:10px">'+i+'</div>');
}
for (i=0; i < M.length; i++){
document.write('<div id="Ny'+i+'" style="position:absolute;top:0px;left:0px;width:2px;height:2px;font-size:2px;background:#'+mCol+'"></div>');
}
for (i=0; i < H.length; i++){
document.write('<div id="Nz'+i+'" style="position:absolute;top:0px;left:0px;width:2px;height:2px;font-size:2px;background:#'+hCol+'"></div>');
}
for (i=0; i < S.length; i++){
document.write('<div id="Nx'+i+'" style="position:absolute;top:0px;left:0px;width:2px;height:2px;font-size:2px;background:#'+sCol+'"></div>');
}
}
if (NS4){
dgts='1 2 3 4 5 6 7 8 9 10 11 12';
dgts=dgts.split(' ')
for (i=0; i < dots; i++){
document.write('<layer name=nsDigits'+i+' top=0 left=0 height=30 width=30><center><font face=Arial size=1 color='+fCol+'>'+dgts[i]+'</font></center></layer>');
}
for (i=0; i < M.length; i++){
document.write('<layer name=ny'+i+' top=0 left=0 bgcolor='+mCol+' clip="0,0,2,2"></layer>');
}
for (i=0; i < H.length; i++){
document.write('<layer name=nz'+i+' top=0 left=0 bgcolor='+hCol+' clip="0,0,2,2"></layer>');
}
for (i=0; i < S.length; i++){
document.write('<layer name=nx'+i+' top=0 left=0 bgcolor='+sCol+' clip="0,0,2,2"></layer>');
}
}
if (IE4){
document.write('<div style="position:absolute;top:0px;left:0px"><div style="position:relative">');
for (i=1; i < dots+1; i++){
document.write('<div id="ieDigits" style="position:absolute;top:0px;left:0px;width:30px;height:30px;font-family:Arial;font-size:10px;color:'+fCol+';text-align:center;padding-top:10px">'+i+'</div>');
}
document.write('</div></div>')
document.write('<div style="position:absolute;top:0px;left:0px"><div style="position:relative">');
for (i=0; i < M.length; i++){
document.write('<div id=y style="position:absolute;width:2px;height:2px;font-size:2px;background:'+mCol+'"></div>');
}
document.write('</div></div>')
document.write('<div style="position:absolute;top:0px;left:0px"><div style="position:relative">');
for (i=0; i < H.length; i++){
document.write('<div id=z style="position:absolute;width:2px;height:2px;font-size:2px;background:'+hCol+'"></div>');
}
document.write('</div></div>')
document.write('<div style="position:absolute;top:0px;left:0px"><div style="position:relative">');
for (i=0; i < S.length; i++){
document.write('<div id=x style="position:absolute;width:2px;height:2px;font-size:2px;background:'+sCol+'"></div>');
}
document.write('</div></div>')
}

function clock(){
time = new Date ();
secs = time.getSeconds();
sec = -1.57 + Math.PI * secs/30;
mins = time.getMinutes();
min = -1.57 + Math.PI * mins/30;
hr = time.getHours();
hrs = -1.57 + Math.PI * hr/6 + Math.PI*parseInt(time.getMinutes())/360;

if (NS6){
Ypos=window.pageYOffset+window.innerHeight-Ybase-25;
Xpos=window.pageXOffset+window.innerWidth-Xbase-30;
for (i=1; i < dots+1; i++){
 document.getElementById("n6Digits"+i).style.top=Ypos-15+Ybase*Math.sin(-1.56 +i *Split*Math.PI/180)
 document.getElementById("n6Digits"+i).style.left=Xpos-15+Xbase*Math.cos(-1.56 +i*Split*Math.PI/180)
 }
for (i=0; i < S.length; i++){
 document.getElementById("Nx"+i).style.top=Ypos+i*Ybase/4.1*Math.sin(sec);
 document.getElementById("Nx"+i).style.left=Xpos+i*Xbase/4.1*Math.cos(sec);
 }
for (i=0; i < M.length; i++){
 document.getElementById("Ny"+i).style.top=Ypos+i*Ybase/4.1*Math.sin(min);
 document.getElementById("Ny"+i).style.left=Xpos+i*Xbase/4.1*Math.cos(min);
 }
for (i=0; i < H.length; i++){
 document.getElementById("Nz"+i).style.top=Ypos+i*Ybase/4.1*Math.sin(hrs);
 document.getElementById("Nz"+i).style.left=Xpos+i*Xbase/4.1*Math.cos(hrs);
 }
}
if (NS4){
Ypos=window.pageYOffset+window.innerHeight-Ybase-20;
Xpos=window.pageXOffset+window.innerWidth-Xbase-30;
for (i=0; i < dots; ++i){
 document.layers["nsDigits"+i].top=Ypos-5+Ybase*Math.sin(-1.045 +i*Split*Math.PI/180)
 document.layers["nsDigits"+i].left=Xpos-15+Xbase*Math.cos(-1.045 +i*Split*Math.PI/180)
 }
for (i=0; i < S.length; i++){
 document.layers["nx"+i].top=Ypos+i*Ybase/4.1*Math.sin(sec);
 document.layers["nx"+i].left=Xpos+i*Xbase/4.1*Math.cos(sec);
 }
for (i=0; i < M.length; i++){
 document.layers["ny"+i].top=Ypos+i*Ybase/4.1*Math.sin(min);
 document.layers["ny"+i].left=Xpos+i*Xbase/4.1*Math.cos(min);
 }
for (i=0; i < H.length; i++){
 document.layers["nz"+i].top=Ypos+i*Ybase/4.1*Math.sin(hrs);
 document.layers["nz"+i].left=Xpos+i*Xbase/4.1*Math.cos(hrs);
 }
}

if (IE4){
Ypos=document.body.scrollTop+window.document.body.clientHeight-Ybase-20;
Xpos=document.body.scrollLeft+window.document.body.clientWidth-Xbase-20;
for (i=0; i < dots; ++i){
 ieDigits[i].style.pixelTop=Ypos-15+Ybase*Math.sin(-1.045 +i *Split*Math.PI/180)
 ieDigits[i].style.pixelLeft=Xpos-15+Xbase*Math.cos(-1.045 +i *Split*Math.PI/180)
 }
for (i=0; i < S.length; i++){
 x[i].style.pixelTop =Ypos+i*Ybase/4.1*Math.sin(sec);
 x[i].style.pixelLeft=Xpos+i*Xbase/4.1*Math.cos(sec);
 }
for (i=0; i < M.length; i++){
 y[i].style.pixelTop =Ypos+i*Ybase/4.1*Math.sin(min);
 y[i].style.pixelLeft=Xpos+i*Xbase/4.1*Math.cos(min);
 }
for (i=0; i < H.length; i++){
 z[i].style.pixelTop =Ypos+i*Ybase/4.1*Math.sin(hrs);
 z[i].style.pixelLeft=Xpos+i*Xbase/4.1*Math.cos(hrs);
 }
}
setTimeout('clock()',100);
}
clock();
//-->
</script>

Code một trang đồng hồ mẫu hoàn chỉnh.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 <html xmlns="http://www.w3.org/1999/xhtml">
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
 <title>Dong ho bang JavaScript By VnTim</title>
 </head>

<body>
 <form name="BM1">
 <input type="text" name="MucVB">
 </form>

<script language="javascript">
 function HamThoiGian(){
 // Khoi tao doi tuong thoi gian.
 var ThoiGian = new Date(); // Khoi tao doi tuong Date.
 var Gio = ThoiGian.getHours(); // Lay gia tri gio tu doi tuong Date.
 var Phut = ThoiGian.getMinutes(); // Lay phút tu doi tuong Date.
 var Giay = ThoiGian.getSeconds(); // Lay giây tu doi tuong Date
 // Thêm so 0 vào truoc so chi thoi gian neu nhu nó nho hon 10.
 if(Gio<10){
 Gio="0"+Gio;}
 if(Phut<10){
 Phut="0"+Phut;}
 if(Giay<10){
 Giay="0"+Giay;}
 // Xuat ket qua ra muc nhap van ban có tên MucVB
 document.BM1.MucVB.value="Bay gio la: "+Gio+":"+Phut+":"+Giay;
 // Goi lai hàm HamThoiGian sau moi mot giây trôi qua.
 }
 setInterval("HamThoiGian()",1000); // Su dung setInterval de goi lap di lap lai hàm HamThoiGian sau 1 giây.
 </script>

</body>
 </html>