如下代碼，為什么點(diǎn)擊開(kāi)始按鈕，然后點(diǎn)更改時(shí)間間隔按鈕，這時(shí)再點(diǎn)停止按鈕時(shí)就失效了。點(diǎn)開(kāi)始后再點(diǎn)停止，就能正常停止。
<!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"?xml:lang="en">
<head>
<meta?http-equiv="Content-Type"?content="text/html;charset=UTF-8">
<title>定時(shí)函數(shù)</title>
<script?type="text/javascript">
var?n?=?0;
var?timer;
function?t()?{
document.getElementById('b').innerHTML?=?'數(shù)字：'?+?(++n);
}
function?kaiShi()?{
timer?=?setInterval("t()",1000);
}
???function?quit()?{
????var?tui?=?clearInterval(timer);
???}
???function?gai()?{
timer?=?setInterval("t()",500);
???}
</script>
</head>
<body>
<label?id='b'></label>
<input?type="button"?name=""?value="start"?onclick="kaiShi()">
<input?type="button"?name=""?value="停止"?onclick="quit()">
<input?type="button"?name=""?value='更改時(shí)間間隔為0.5秒'?onclick="gai()">
</body>
</html>
javascript定時(shí)函數(shù)問(wèn)題
fenkapian
2016-07-04 20:18:37
