运行效果截图如下：
具体代码如下：
<html> <head> <title>js倒计时</title> <SCRIPT language=JavaScript1.2> function setcountdown(theyear,themonth,theday){ yr=theyear;mo=themonth;da=theday } setcountdown(2016,8,5) var occasion="2016巴西奥运会" var message_on_occasion="盼望已久的时刻终于来到了!" var countdownwidth='480px' var countdownheight='20px' var countdownbgcolor='tan' var opentags='<font face="宋体"><small>' var closetags='</small></font>' var montharray=new Array("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec") var crosscount='' function start_countdown(){ if (document.layers) document.countdownnsmain.visibility="show" else if (document.all||document.getElementById) crosscount=document.getElementById&&!document.all?document.getElementById("countdownie") : countdownie countdown() } if (document.all||document.getElementById) document.write('<span></span>') window.onload=start_countdown function countdown(){ var today=new Date() var todayy=today.getYear() if (todayy < 1000) todayy+=1900 var todaym=today.getMonth() var todayd=today.getDate() var todayh=today.getHours() var todaymin=today.getMinutes() var todaysec=today.getSeconds() var todaystring=montharray[todaym]+" "+todayd+", "+todayy+" "+todayh+":"+todaymin+":"+todaysec futurestring=montharray[mo-1]+" "+da+", "+yr dd=Date.parse(futurestring)-Date.parse(todaystring) dday=Math.floor(dd/(60*60*1000*24)*1) dhour=Math.floor((dd%(60*60*1000*24))/(60*60*1000)*1) dmin=Math.floor(((dd%(60*60*1000*24))%(60*60*1000))/(60*1000)*1) dsec=Math.floor((((dd%(60*60*1000*24))%(60*60*1000))%(60*1000))/1000*1) if(dday<=0&&dhour<=0&&dmin<=0&&dsec<=1&&todayd==da){ if (document.layers){ document.countdownnsmain.document.countdownnssub.document.write(opentags+message_on_occasion+closetags) document.countdownnsmain.document.countdownnssub.document.close() } else if (document.all||document.getElementById) crosscount.innerHTML=opentags+message_on_occasion+closetags return } else if (dday<=-1){ if (document.layers){ document.countdownnsmain.document.countdownnssub.document.write(opentags+"时间已经过了!"+closetags) document.countdownnsmain.document.countdownnssub.document.close() } else if (document.all||document.getElementById) crosscount.innerHTML=opentags+"Occasion already passed! "+closetags return } else{ if (document.layers){ document.countdownnsmain.document.countdownnssub.document.write(opentags+dday+ " days, "+dhour+" hours, "+dmin+" minutes, and "+dsec+" seconds left until "+occasion+closetags) document.countdownnsmain.document.countdownnssub.document.close() } else if (document.all||document.getElementById) crosscount.innerHTML=opentags+"还有 "+dday+ " 天, "+dhour+" 小时, "+dmin+" 分, "+dsec+" 秒 就是 "+occasion+closetags } setTimeout("countdown()",1000) } </SCRIPT> <SCRIPT type="text/javascript" src=""></SCRIPT> <SCRIPT language="JavaScript"> <!-- BaiduWriteAD("zouwenyedg","3"); //--> </SCRIPT> </head> <body> <ILAYER id=countdownnsmain visibility="hide" bgColor="&{countdownbgcolor};"><LAYER id=countdownnssub top="0" left="0"></LAYER></ILAYER> </body> </html>