<script> function startTime(){ var today=new Date(); var h=today.getHours(); var m=today.getMinutes(); var s=today.getSeconds(); h=checkTime(h); m=checkTime(m); 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>
原文：http://www.cnblogs.com/soyo/p/6788825.html