如何讓程序按照文本框中的秒數(shù)進(jìn)行倒計(jì)時(shí)?
這是我的代碼,直接運(yùn)行,num是空,總是要程序運(yùn)行一次,num才變化
<!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>
? <!--先編寫好網(wǎng)頁(yè)布局-->
? <h2>操作成功</h2>
? <p><span id="countnum">10</span>秒后回到首頁(yè) <a href="javascript:window.history.forward()">返回</a></p>
? <form action="" name="form1">
? <input type="button" name="" value="開始"onclick="count()" id="button1">
??? <input type="button" name="" value="停止" id="button2" onclick="stop()">
??? <input type="text" name="" value="" placeholder="" id="second">
??????? <script type="text/javascript">
??????? var num = parseInt(document.getElementById("second").value)
??????? var i
??????? function count(){
??????????? if (num>0) {
??????????????? window.document.getElementById("countnum").innerHTML = num
??????????????? document.getElementById("button1").disabled = true
??????????? } else{
??????????????? document.getElementById("button1").disabled = false
??????????????? window.location.href = "http:www.baidu.com"
??????????? };
??????? num--
??????? i = setTimeout("count()", 1000)
??????? }
??? function stop () {
??????? clearTimeout(i)
??????? document.getElementById("button1").disabled = false
??????? // body...
??? }
?? //獲取顯示秒數(shù)的元素，通過定時(shí)器來更改秒數(shù)。
?? //通過window的location和history對(duì)象來控制網(wǎng)頁(yè)的跳轉(zhuǎn)。
? ?
?</script>
</form>
</body>
</html>
2015-11-17
用innerHTML的屬性直接替換 HTML 元素的內(nèi)容。
2015-10-27
<!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>
? <!--先編寫好網(wǎng)頁(yè)布局-->
? <h2>操作成功</h2>
? <p><span id="countnum">10</span>秒后回到首頁(yè) <a href="javascript:window.history.forward()">返回</a></p>
? <form action="" name="form1">
? <input type="button" name="" value="開始"onclick="count()" id="button1">
??? <input type="button" name="" value="停止" id="button2" onclick="stop()">
??? <input type="text" name="" value="" placeholder="" id="second" onblur="aa()">
??? <!-- 添加一個(gè)文本框失焦的事件,在此函數(shù)中給num賦值并返回num即可, -->
??????? <script type="text/javascript">
??????? var num //將num定義為全局變量
??????? var i
??????? function aa(){
??????????? num = parseInt(document.getElementById("second").value)
??????????? return num
??????? }
??????? function count(){
??????????? if (num>0) {
??????????????? window.document.getElementById("countnum").innerHTML = num
??????????????? document.getElementById("button1").disabled = true
??????????? } else{
??????????????? document.getElementById("button1").disabled = false
??????????????? window.location.href = "http:www.baidu.com"
??????????? };
??????? num--
??????? i = setTimeout("count()", 1000)
??????? }
??? function stop () {
??????? clearTimeout(i)
??????? document.getElementById("button1").disabled = false
??????? document.getElementById("second").focus()
??????? document.getElementById("second").select()
??????? // body...
??? }
?? //獲取顯示秒數(shù)的元素，通過定時(shí)器來更改秒數(shù)。
?? //通過window的location和history對(duì)象來控制網(wǎng)頁(yè)的跳轉(zhuǎn)。
? ?
?</script>
</form>
</body>
</html>
已經(jīng)解決了,主要就是文本框中的值在改變之后要給num復(fù)制,所以我增加了一個(gè)文本框的失焦時(shí)間來給num賦值.
2015-10-26
var count = document.getElementById('count');
?? ??? ?var a = document.getElementsByTagName('a')[0];
?? ??? ?var num = 5;
?? ??? ?var timer = setInterval(function? () {
?? ??? ??? ??? ??? ?
?? ??? ??? ?
?? ??? ??? ??? ?num--;
?? ??? ??? ??? ?count.innerHTML = num;
?? ??? ??? ??? ?if (num == 0) {
?? ??? ??? ??? ??? ??? ?//window.history.back();
?? ??? ??? ??? ??? ?count.innerHTML = 0;
?? ??? ??? ??? ??? ?clearInterval(timer);
?? ??? ??? ??? ?} else{
?? ??? ??? ??? ?};