不知道錯(cuò)在哪兒了 求大神解答TAT
<!DOCTYPE?html>
<html>
<head>
????<title>瀏覽器對(duì)象</title>
????<meta?http-equiv="Content-Type"?content="text/html;?charset=gkb"?/>
</head>
<body>
????<!--先編寫好網(wǎng)頁布局-->
????<h3><b>操作成功</b></h3>
????<span?id="ms">5</sapn>秒后回到主頁 <a?href="#"?onclick="goBack()">返回</a>
?
??<script?type="text/javascript">??
?
???//獲取顯示秒數(shù)的元素，通過定時(shí)器來更改秒數(shù)。
???var?num=6;
????function?clock()
????{
????????document.getElementById("ms").innerHTML=num-1;
????}
????num--;
????setInterval("clock()",1000);
???//通過window的location和history對(duì)象來控制網(wǎng)頁的跳轉(zhuǎn)。
???function?goBack()
???{
???????window.history.back;
???}
?</script>?
</body>
</html>
2019-10-10
<body?onload="clock()">?? <!--先編寫好網(wǎng)頁布局-->?? <h3><b>操作成功</b></h3>?? <!--?<span?id="ms">5</sapn>?標(biāo)簽寫錯(cuò)了?-->?? <span?id="ms">5</span>秒后回到主頁 <a?href="#"?onclick="goBack()">返回</a>???? <script?type="text/javascript">?????? //獲取顯示秒數(shù)的元素，通過定時(shí)器來更改秒數(shù)。?????? var?num?=?6;?????? function?clock()?{???????? //?document.getElementById("ms").innerHTML=num-1;-->?寫了num--?以后不需要寫這個(gè)???????? num--;???????? document.getElementById("ms").innerHTML?=?num;???????????????? if?(num?==?0)?{?????????? window.location.replace('http://www.baidu.com')?????????? return;???????? }???????? //?num--;挪進(jìn)方法里邊???????? setTimeout("clock()",?1000);??????????????? }?????? //通過window的location和history對(duì)象來控制網(wǎng)頁的跳轉(zhuǎn)。?????? function?goBack()?{???????? //?window.history.back===>要加括號(hào)調(diào)用;???????? window.history.back();?????? }???? </script> </body>然后如果你要看setIterval的寫法可以參考我上一個(gè)回答，
setTimeout：是從現(xiàn)在算起多少ms后運(yùn)行該代碼（只運(yùn)行一次），執(zhí)行完銷毀重新創(chuàng)建，至始至終只有一個(gè)存在
setInterval：是每隔多少ms運(yùn)行一次代碼，這個(gè)代碼會(huì)不斷的執(zhí)行的，不清楚繼續(xù)使用會(huì)出現(xiàn)出現(xiàn)多個(gè)定時(shí)器一起計(jì)時(shí)
2019-10-10
<!DOCTYPE?html> <html>? <head>?? <title>瀏覽器對(duì)象</title>???? <meta?http-equiv="Content-Type"?content="text/html;?charset=utf-8"/>???? </head>? <body?onload="timerb()">?? <!--先編寫好網(wǎng)頁布局-->?? <h3>操作成功</h3>?? <p?id="p1"></p>?? <button?onclick="goBack()">返回</button>????? <script?type="text/javascript">?????? ????//獲取顯示秒數(shù)的元素，通過定時(shí)器來更改秒數(shù)。??? ????var?num?=?10;???? ????var?timer?=?null;???? ????function?timerb()?{?????? ????????document.getElementById('p1').innerHTML?=?num?+?'秒后跳到首頁'?????? ????????num--;?????? ????????if?(!timer)?{???????? ????????????timer?=?setInterval("timerb()",?1000)????? ?????????}?????? ?????????if?(num?===?0)?{???????? ?????????????timer?=?null;???????? ?????????????location.replace('http://www.baidu.com')?????? ?????????}???? ?????}???? ?????//通過window的location和history對(duì)象來控制網(wǎng)頁的跳轉(zhuǎn)。??? ?????function?goBack(){??????? ?????????window.history.back()??? ?????}? ?</script>? ?</body> ?</html>